Fast ion exchangeable glasses with high indentation threshold

ABSTRACT

Alkali aluminosilicate glasses that are ion exchangeable to high compressive stresses, have fast ion exchange kinetics, and high intrinsic damage resistance. The glasses achieve all of the above desired properties either with only small amounts of P2O5 (&lt;1 mol %) or without addition of any P2O5.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 15/986,402, filed May 22, 2018, which is a continuation of U.S. application Ser. No. 14/543,925, filed Nov. 18, 2014, which claims the benefit of priority to U.S. Provisional Application No. 61/909,049 filed on Nov. 26, 2013, each of which is incorporated herein by reference in its entirety.

BACKGROUND

The disclosure relates to alkali aluminosilicate glasses that are ion exchangeable to high compressive stresses, have fast ion exchange kinetics, and high intrinsic damage resistance.

SUMMARY

The present disclosure provides alkali aluminosilicate glasses that are ion exchangeable to high compressive stresses, have fast ion exchange kinetics, and high intrinsic damage resistance. The glasses described herein achieve all of the above desired properties either with only small amounts of P₂O₅ (<1 mol %) or without addition of any P₂O₅.

Accordingly, one aspect of the disclosure is to provide a glass comprising: from about 50 mol % to about 72 mol % SiO₂; from about 12 mol % to about 22 mol % Al₂O₃; up to about 6.5 mol % B₂O₃; up to about 1 mol % P₂O₅; from about 11 mol % to about 21 mol % Na₂O; up to about 0.95 mol % K₂O; up to about 4 mol % MgO; up to about 5 mol % ZnO; and up to about 2 mol % CaO. In some embodiments, Na₂O+K₂O—Al₂O₃≤2.0 mol. In some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>1 mol %. In some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>1 mol %. In some embodiments, 24 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag.

A second aspect of the disclosure is to provide a glass comprising from about 55 mol % to about 62 mol % SiO₂; from about 16 mol % to about 20 mol % Al₂O₃; from about 4 mol % to about 6.5 mol % B₂O₃; from about 14 mol % to about 18 mol % Na₂O; from about 0.2 mol % to about 0.75 mol % K₂O; up to about 0.5 mol % MgO; up to about 0.5 mol % ZnO; and up to about 0.5 mol % CaO, wherein the glass is substantially free of P₂O₅. In some embodiments, Na₂O+K₂O—Al₂O₃ 0.5 mol %. In some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>4 mol %. In some embodiments, 28 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag. In some embodiments, the glasses are substantially free of TiO₂.

Another aspect is to provide a method of ion exchanging a glass. The method comprises ion exchanging an alkali aluminosilicate glass for up to about eight hours in an ion exchange bath at a temperature of about 410° C. or less. The ion exchange bath comprises a potassium salt and the alkali aluminosilicate glass comprising: from about 50 mol % to about 72 mol % SiO₂; from about 12 mol % to about 22 mol % Al₂O₃; up to about 6.5 mol % B₂O₃; up to about 1 mol % P₂O₅; from about 11 mol % to about 21 mol % Na₂O; up to about 0.95 mol % K₂O; up to about 4 mol % MgO; up to about 5 mol % ZnO; and up to about 1 mol % CaO. The ion exchanged alkali aluminosilicate glass has a compressive layer extending from a surface to a depth of layer DOL, the compressive layer having a compressive stress CS of at least about 500 MPa. In some embodiments, the glasses are substantially free of TiO₂.

These and other aspects, advantages, and salient features will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of an ion exchanged glass article.

DETAILED DESCRIPTION

In the following description, like reference characters designate like or corresponding parts throughout the several views shown in the FIGURES. It is also understood that, unless otherwise specified, terms such as “top,” “bottom,” “outward,” “inward,” and the like are words of convenience and are not to be construed as limiting terms. In addition, whenever a group is described as comprising at least one of a group of elements and combinations thereof, it is understood that the group may comprise, consist essentially of, or consist of any number of those elements recited, either individually or in combination with each other. Similarly, whenever a group is described as consisting of at least one of a group of elements or combinations thereof, it is understood that the group may consist of any number of those elements recited, either individually or in combination with each other. Unless otherwise specified, a range of values, when recited, includes both the upper and lower limits of the range as well as any ranges therebetween. As used herein, the indefinite articles “a,” “an,” and the corresponding definite article “the” mean “at least one” or “one or more,” unless otherwise specified. It also is understood that the various features disclosed in the specification and the drawings can be used in any and all combinations.

As used herein, the terms “glass article” and “glass articles” are used in their broadest sense to include any object made wholly or partly of glass. Unless otherwise specified, all compositions are expressed in terms of mole percent (mol %). Coefficients of thermal expansion (CTE) are expressed in terms of 10⁻⁷/° C. and represent a value measured over a temperature range from about 20° C. to about 300° C., unless otherwise specified.

As used herein, the term “anneal point,” refers to the temperature at which a glass has a viscosity of 10^(13.2) poise, the term “strain point” refers to the temperature at which a glass has a viscosity of 10^(14.7) poise, and the term “softening point” refers to the temperature at which glass visibly softens under its own weight.

It is noted that the terms “substantially” and “about” may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. Thus, a glass that is “substantially free of MgO” is one in which MgO is not actively added or batched into the glass, but may be present in very small amounts as a contaminant.

Vickers crack initiation thresholds described herein are determined by applying and then removing an indentation load to the glass surface at a rate of 0.2 mm/min. The maximum indentation load is held for 10 seconds. The indentation cracking threshold is defined at the indentation load at which 50% of 10 indents exhibit any number of radial/median cracks emanating from the corners of the indent impression. The maximum load is increased until the threshold is met for a given glass composition. All indentation measurements are performed at room temperature in 50% relative humidity.

Compressive stress and depth of layer are measured using those means known in the art. Such means include, but are not limited to, measurement of surface stress (FSM) using commercially available instruments such as the FSM-6000, manufactured by Luceo Co., Ltd. (Tokyo, Japan), or the like, and methods of measuring compressive stress and depth of layer are described in ASTM 1422C-99, entitled “Standard Specification for Chemically Strengthened Flat Glass,” and ASTM 1279.19779 “Standard Test Method for Non-Destructive Photoelastic Measurement of Edge and Surface Stresses in Annealed, Heat-Strengthened, and Fully-Tempered Flat Glass,” the contents of which are incorporated herein by reference in their entirety. Surface stress measurements rely upon the accurate measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass. SOC in turn is measured by those methods that are known in the art, such as fiber and four point bend methods, both of which are described in ASTM standard C770-98 (2008), entitled “Standard Test Method for Measurement of Glass Stress-Optical Coefficient,” the contents of which are incorporated herein by reference in their entirety, and a bulk cylinder method.

Referring to the drawings in general and to FIG. 1 in particular, it will be understood that the illustrations are for the purpose of describing particular embodiments and are not intended to limit the disclosure or appended claims thereto. The drawings are not necessarily to scale, and certain features and certain views of the drawings may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

Disclosed herein are alkali aluminosilicate glasses that are ion exchangeable to high compressive stresses, have fast ion exchange kinetics, and high intrinsic damage resistance. Previously, glasses exhibiting all three of these features contain large amounts of P₂O₅. The glasses described herein achieve all of the above desired properties either with only small amounts of P₂O₅ (<1 mol %) or without addition of any P₂O₅.

Ion exchange is commonly used to chemically strengthen glasses. In one particular example, alkali cations within a source of such cations (e.g., a molten salt, or “ion exchange,” bath) are exchanged with smaller alkali cations within the glass to achieve a layer that is under a compressive stress (CS) near the surface of the glass. For example, potassium ions from the cation source are often exchanged with sodium ions within the glass. Alternatively, other monovalent cations such as, Ag⁺, Cu⁺, Tl⁺, or the like may be introduced into the glass via such ion exchange. The compressive layer extends from the surface to a depth of layer (DOL) within the glass.

A cross-sectional schematic view of a planar ion exchanged glass article is shown in FIG. 1. Glass article 100 has a thickness t, first surface 110, and second surface 112. While the embodiment shown in FIG. 1 depicts glass article 100 as a flat planar sheet or plate, glass article may have other configurations, such as three dimensional shapes or non-planar configurations. Glass article 100 has a first compressive layer 120 extending from first surface 110 to a depth of layer d₁ into the bulk of the glass article 100. In the embodiment shown in FIG. 1, glass article 100 also has a second compressive layer 122 extending from second surface 112 to a second depth of layer d₂. Glass article also has a central region 130 that extends from d₁ to d₂. Central region 130 is under a tensile stress or central tension (CT), which balances or counteracts the compressive stresses of layers 120 and 122. The depth d₁, d₂ of first and second compressive layers 120, 122 protects the glass article 100 from the propagation of flaws introduced by sharp impact to first and second surfaces 110, 112 of glass article 100, while the compressive stress minimizes the likelihood of a flaw penetrating through the depth d₁, d₂ of first and second compressive layers 120, 122.

The high amounts of Al₂O₃ (12 mol % to 22 mol %) and Na₂O (11 mol % to 21 mol %) in the glasses described herein enable the glass to be ion exchanged to achieve high levels of compressive stress CS. In some embodiments, the glasses described herein may be ion exchanged to produce compressive layers 120, 122 having a compressive stress CS of at least about 500 MPa; in some embodiments, at least about 700 MPa; in other embodiments, at least about 800 MPa; in other embodiments, at least about 900 MPa; in other embodiments, at least about 1000 MPa; and, in still other embodiments, at least about 1100 MPa. In some embodiments, the glasses described herein may be ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 52 μm within eight hours ion exchange time. In other embodiments, the glasses described herein may be ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 40 μm within four hours ion exchange time. In still other embodiments, the glasses described herein may be ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 30 μm within two hours ion exchange time. In some embodiments, the compressive stress is in a range from about 700 MPa to about 1200 MPa; in other embodiments, from about 800 MPa to about 1200 MPa; in still other embodiments, from about 900 MPa to about 1200 MPa.

When ion exchanged, the glasses described herein exhibit intrinsic damage resistance, as reflected by Vickers indentation threshold measurements, described hereinabove. When the value of the expression B₂O₃—(Na₂O+K₂O—Al₂O₃) is high (>1 mol %) and the value of (Na₂O+K₂O—Al₂O₃) is low (0.5 mol %), the lass exhibits high levels of damage resistance. In some embodiments, the ion exchanged glass has a Vickers crack indentation threshold of at least about 9.5 kgf; in some embodiments, at least about 17.5 kgf; in other embodiments, at least about 22.5 kgf; in other embodiments, at least about 32.5 kgf; and, in still other embodiments, at least about 40 kgf.

High rates of ion exchange are attributable to the combination of several compositional factors, including high concentrations of Al₂O₃ (12 mol % to 22 mol %) and RAlO₄ (24 mol % to 45 mol %); a non-zero K₂O concentration (up to about 0.95 mol % K₂O); and low concentration (0 mol % to 5 mol %) of divalent metal oxides RO (R′ is at least one of Ca. Mg, and Zn). In some embodiments, the glasses described herein are ion exchangeable at a rate to achieve a CS·DOL product of at least 44000 MPa·μm within less than about 8 hours.

The glasses described herein, in some embodiments, have a liquidus viscosity of at least about 100 kiloPoise (kpoise), which enables them to be made using down-draw techniques known in the art, such as fusion draw and slot draw methods. In particular, these glasses are compatible (i.e., do not substantially react with or degrade) with alumina hardware, such as isopipes) used in the fusion draw process.

In some embodiments, the glasses described herein consist essentially of or comprise: from about 50 mol % to about 72 mol % SiO₂ (i.e., 50 mol %≤SiO₂≤72 mol %); from about 12 mol % to about 22 mol % Al₂O₃ (i.e., 12 mol %≤Al₂O₃≤22 mol %); up to about 6.5 mol % B₂O₃ (i.e., 0 mol %≤B₂O₃≤6.5 mol %); up to about 1 mol % P₂O₅ (i.e., 0 mol %≤P₂O₅≤1 mol %); from about 11 mol % to about 21 mol % Na₂O (i.e., 11 mol %≤Na₂O≤21 mol %); up to about 0.95 mol % K₂O (i.e., 0 mol %≤K₂O≤0.95 mol %); up to about 4 mol % MgO (i.e., 0 mol %≤MgO≤4 mol %); up to about 5 mol % ZnO (i.e., 0 mol %≤ZnO≤4 mol %); and up to about 2 mol % CaO (i.e., 0 mol %≤CaO≤2 mol %). In some embodiments, Na₂O+K₂O—Al₂O₃≤2.0 mol % and, in some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>1 mol %. In some embodiments, 24 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag. In some embodiments, 56 mol %≤SiO₂+B₂O₃≤78 mol % and, in some embodiments, 0 mol %≤Σ[R′O]≤5 mol %, where R′ is at least one of Ca. Mg, and Zn. In some embodiments, 2 mol %≤B₂O₃+P₂O₅≤7.5 mol %. In some embodiments, the glasses described herein are substantially free of TiO₂.

In certain embodiments, the glass is substantially free of, or contains 0 mol %, P₂O₅. The glass, in some embodiments, is substantially free of, or contains 0 mol %, Li₂O. In some embodiments, the glass is substantially free of As₂O₃ and Sb₂O₅.

In some embodiments, the glass may further include at least one fining agent such as SnO₂, CeO₂, As₂O₃, Sb₂O₅, Cl⁻, F⁻, or the like. In some embodiments, the glass may include up to about 0.5 mol % SnO₂ (i.e., 0 mol %≤SnO₂≤0.5 mol %); up to about 0.5 mol % Sb₂O₅, (i.e., 0 mol %≤CeO₂≤0.5 mol %); and/or up to about 0.5 mol % As₂O₃ (i.e., 0 mol %≤As₂O₃≤0.5 mol %.

In particular embodiments, the glasses consist essentially of or comprise: from about 55 mol % to about 62 mol % SiO₂ (i.e., 55 mol %≤SiO₂≤62 mol %); from about 16 mol % to about 20 mol % Al₂O₃ (i.e., 16 mol %<Al₂O₃≤20 mol %); from about 2 mol % to about 6.5 mol % B₂O₃ (i.e., 2 mol %≤B₂O₃≤6.5 mol %); up to about 1 mol % P₂O₅ (i.e., 0 mol %≤P₂O₅≤1 mol %); from about 14 mol % to about 18 mol % Na₂O (i.e., 14 mol %≤Na₂O≤18 mol %); from about 0.2 mol % to about 0.75 mol % K₂O (i.e., 0.2 mol %≤K₂O≤0.95 mol %); up to about 0.5 mol % MgO (i.e., 0 mol %≤MgO≤0.5 mol %); up to about 0.5 mol % ZnO (i.e., 0 mol %≤ZnO≤0.5 mol %); and up to about 0.5 mol % CaO (i.e., 0 mol %≤CaO≤0.5 mol %). In some embodiments, Na₂O+K₂O—Al₂O₃≤0.5 mol % and, in some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>4 mol %. In some embodiments, 24 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag. In some embodiments, 56 mol %≤SiO₂+B₂O₃≤75 mol % and, in some embodiments, 0 mol %≤Σ[R′O]≤0.5 mol %, where R′ is at least one of Ca. Mg, and Zn. In some embodiments, K₂O≤0.5(Na₂O+K₂O). In embodiments, the glass is substantially free, or contains 0 mol %, of TiO₂. In certain embodiments, the glass is substantially free of, or contains 0 mol %, P₂O₅. The glass, in some embodiments, is substantially free of, or contains 0 mol %, Li₂O. In other embodiments, the glass is substantially free, or contains 0 mol %, of As₂O₃ and Sb₂O₅.

In embodiments, the glass may further include at least one fining agent such as SnO₂, CeO₂, As₂O₃, Sb₂O₅, Cl⁻, F⁻, or the like. In some embodiments, the glass may include up to about 0.5 mol % SnO₂ (i.e., 0 mol % SnO₂ s 0.5 mol %); up to about 0.5 mol % Sb₂O₅, (i.e., 0 mol %≤CeO₂≤0.5 mol %); and/or up to about 0.5 mol % As₂O₃ (i.e., 0 mol %≤As₂O₃≤0.5 mol %.

In still other embodiments, the glasses described herein consist essentially of or comprise: from about 55 mol % to about 62 mol % SiO₂ (i.e., 55 mol %≤SiO₂≤62 mol %); from about 16 mol % to about 20 mol % Al₂O₃ (i.e., 16 mol %<Al₂O₃≤20 mol %); from about 4 mol % to about 6.5 mol % B₂O₃ (i.e., 4 mol %≤B₂O₃≤6.5 mol %); from about 14 mol % to about 18 mol % Na₂O (i.e., 14 mol %≤Na₂O≤18 mol %); from about 0.2 mol % to about 0.75 mol % K₂O (i.e., 0.2 mol %≤K₂O≤4 mol %); up to about 0.5 mol % MgO (i.e., 0 mol %≤MgO≤0.5 mol %); up to about 0.5 mol % ZnO (i.e., 0 mol %≤ZnO≤0.5 mol %); up to about 0.5 mol % CaO (i.e., 0 mol %≤CaO≤0.5 mol %); and are substantially free of, or contain 0 mol %, P₂O₅. In some embodiments, Na₂O+K₂O—Al₂O₃≤0.5 mol % and, in some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>4 mol %. In some embodiments, 28 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag. In some embodiments, 56 mol %≤SiO₂+B₂O₃≤70 mol % and, in some embodiments, 0 mol %≤Σ[R′O]≤0.5 mol %, where R′ is at least one of Ca. Mg, and Zn. In some embodiments, K₂O≤0.25(Na₂O+K₂O). In embodiments, the glass is substantially free of TiO₂. In certain embodiments, the glass is substantially free of, or contains 0 mol %, Li₂O. In some embodiments, the glass is substantially free of, or contains 0 mol %, As₂O₃ and Sb₂O₅.

In some embodiments, the glass may further include at least one fining agent such as SnO₂, CeO₂, As₂O₃, Sb₂O₅, Cl⁻, F⁻, or the like. In some embodiments, the glass may include up to about 0.5 mol % SnO₂ (i.e., 0 mol % SnO₂ s 0.5 mol %); up to about 0.5 mol % Sb₂O₅, (i.e., 0 mol %≤CeO₂≤0.5 mol %); and/or up to about 0.5 mol % As₂O₃ (i.e., 0 mol %≤As₂O₃≤0.5 mol %.

Compositions and non-limiting examples of these glasses that comprise P₂O₅ are listed in Table 1. Compositions and non-limiting examples of these glasses that are substantially free of P₂O₅ are listed in Table 2. Each of the oxide components of these glasses serves a function. Silica (SiO₂), for example, is the primary glass forming oxide, and forms the network backbone for the molten glass. Pure SiO₂ has a low CTE and is alkali metal-free. Due to its extremely high melting temperature, however, pure SiO₂ is incompatible with the fusion draw process. The viscosity curve is also much too high to match with any core glass in a laminate structure. In some embodiments, the amount of SiO₂ in the glasses described herein ranges from about 50 mol % to about 72 mol %. In other embodiments, the SiO₂ concentration ranges from about 55 mol % to about 62 mol %.

In addition to silica, the glasses described herein comprise the network formers Al₂O₃ and B₂O₃ to achieve stable glass formation, low CTE, low Young's modulus, low shear modulus, and to facilitate melting and/or forming. By mixing all three of these network formers in appropriate concentrations, it is possible achieve stable bulk glass formation while minimizing the need for network modifiers such as alkali or alkaline earth oxides, which act to increase CTE and modulus. Like SiO₂, Al₂O₃ contributes to the rigidity to the glass network. Alumina may exist in the glass in either fourfold or fivefold coordination. In some embodiments, the glasses described herein comprise from about 12 mol % to about 22 mol % Al₂O₃ and, in particular embodiments, from about 16 mol % to about 20 mol % Al₂O₃.

Boron oxide (B₂O₃) is also a glass-forming oxide that is used to reduce viscosity and thus improve the ability to melt and form glass. B₂O₃ may exist in either threefold or fourfold coordination in the glass network. Threefold coordinated B₂O₃ is the most effective oxide for reducing the Young's modulus and shear modulus, thus improving the intrinsic damage resistance of the glass. Accordingly, the glasses described herein, in some embodiments, comprise from about 0 mol % up to about 6.5 mol % B₂O₃, in other embodiments, from about 2 mol % to about 6.5 mol % B₂O₃, and in still other embodiments, from about 4 mol % to about 6.0 mol % B₂O₃. In some embodiments, 56 mol %≤SiO₂+B₂O₃≤78 mol % and, in other embodiments, 66 mol %≤SiO₂+B₂O₃≤75 mol %. In certain embodiments, B₂O₃≤Al₂O₃.

The alkali oxides Na₂O and K₂O are used to achieve chemical strengthening of the glass by ion exchange. In some embodiments, the glass includes Na₂O, which can be exchanged for potassium in a salt bath containing, for example, KNO₃. In some embodiments, 0 mol %≤K₂O≤0.95 mol %, and, in certain embodiments, 0.2 mol %≤K₂O≤0.75 mol %. In some embodiments, 11 mol %≤Na₂O≤21 mol %, in other embodiments, 14 mol %≤Na₂O≤18 mol % In other embodiments, 1 mol %≤Li₂O≤15 mol %, and, in certain embodiments, 6 mol %≤Li₂O≤13 mol %. The glasses described herein are substantially free of Li₂O, or comprise 0 mol % Li₂O. %). In some embodiments, Na₂O+K₂O—Al₂O₃≤2.0 mol % and, in other embodiments, Na₂O+K₂O—Al₂O₃≤0.5 mol %. In some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>1 mol % and, in other embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>4 mol %. In some embodiments, 24 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag, and, in other embodiments, 24 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag.

Like B₂O₃, alkaline earth oxides such as MgO and CaO, and other divalent oxides such as ZnO also improve the melting behavior of the glass. However, they also act to increase CTE and Young's and shear moduli. In some embodiments, the glasses described herein comprise up to about 4 mol % MgO, up to about 1 mol % CaO, and up to about 4 mol % ZnO. In other embodiments, these glasses may comprise up to about 0.5 mol % MgO, up to about 0.5 mol % CaO, and up to about 0.5 mol % ZnO. In some embodiments, 0 mol %≤Σ[R′O]≤5 mol % and, in other embodiments, 0 mol %≤Σ[R′O]≤0.5 mol %, where R′ is at least one of Ca. Mg, and Zn.

TiO₂ is commonly used to lower the coefficient of thermal expansion is glasses. However, TiO₂ may negatively impact the light transmitting properties of the glass, such as by absorbing and transmitting light that otherwise would not be absorbed or transmitted by the glass. Accordingly, in embodiments, the glass is substantially free of, or contains 0 mol %, TiO₂.

In order to ensure that the vast majority of B₂O₃ in the glass is in the threefold coordinated state and thereby obtain a high native scratch resistance, Na₂O+K₂O—Al₂O₃≤2.0 mol % and, in some embodiments, Na₂O+K₂O—Al₂O₃≤0.5 mol %. In some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>1 mol % and, and, in some embodiments, B₂O₃—(Na₂O+K₂O—Al₂O₃)>4 mol %.

The glass may also include at least one fining agent such as SnO₂, CeO₂, As₂O₃, Sb₂O₅, Cl⁻, F⁻, or the like in small concentrations to aid in the elimination of gaseous inclusions during melting. In some embodiments, the glass may comprise up to about 0.5 mol % SnO₂, up to about 0.5 mol % As₂O₃, and/or up to about 0.5 mol % Sb₂O₃. However, As₂O₃ and Sb₂O₃ may have adverse affects on the environment and health. Therefore, in some embodiments, the glass is substantially free of, or contains 0 mol %, As₂O₃ and Sb₂O₅.

Non-limiting examples of compositions and their selected physical properties (strain, anneal and softening points, density, CTE, liquidus temperatures, modulus, refractive index, and stress optical coefficient (SOC)) of the glasses described herein comprising up to about 1 mol % P₂O₅ are listed in Table 1. Non-limiting examples of compositions and their selected physical properties of the glasses described herein that do not contain P₂O₅ are listed in Table 2.

In another aspect, a method of ion exchanging the alkali aluminosilicate glasses described herein above is provided. The method comprises ion exchanging the glass at temperatures of up to about 410° C. for up to about eight hours in an ion exchange bath comprising a potassium salt to form a compressive layer having a compressive stress CS of at least 500 MPa and extending from a surface to a depth of layer DOL. In some embodiments, the glasses described herein may be ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 52 μm within eight hours ion exchange time. In other embodiments, the glasses described herein may be ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 40 μm within four hours ion exchange time. In still other embodiments, the glasses described herein may be ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 30 μm within two hours ion exchange time. In some embodiments, CS·DOL=44000 MPa·μm.

TABLE 1 Compositions and selected physical properties of the glasses described herein comprising up to about 1 mol % P₂O₅. Glass (mol %) A B C D E SiO₂ 63.53 64.65 63.58 64.55 64.63 Al₂O₃ 14.98 14 14 13.97 14.38 B₂O₃ 6.046 6.937 6.983 7.015 6.016 Na₂O 13.76 12.74 13.75 13.73 13.76 K₂O 0.503 0.496 0.501 0.005 0.501 MgO 0.039 0.037 0.037 0.042 0.02 CaO 0.07 0.07 0.068 0.068 0.064 ZnO 0 0 0 0 0 P₂O₅ 0.97 0.97 0.97 0.51 0.497 SnO₂ 0.1 0.1 0.101 0.099 0.099 [Na₂O] + [K₂O] − −0.71 −0.76 0.242 −0.23 −0.12 [Al₂O₃] [B₂O₃] − ([Na₂O] + 6.76 7.701 6.741 7.244 6.135 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 590 575 559 576 570 Anneal Pt. (° C.) 649 634 613 633 629 Soft Pt. (° C.) 935 906 879 914 919 CTE (10⁷° C.⁻¹) 80.6 77.3 80.5 78 80.3 Density (g/cm³) 2.374 2.361 2.374 2.367 2.378 E Mod (Mpsi) 9.26 9.14 9.239 9.165 9.357 G Mod (Mpsi) 3.816 3.764 3.788 3.778 3.864 ν (Poisson's ratio) 0.213 0.214 0.219 0.213 0.211 Indentation Threshold 30 27.5 25 30 32.5 (kgf) CS¹ (MPa) 803.4 724.9 733.1 782.1 792.5 DOL¹ (μm) 70.09 64.23 60.75 58.71 62.94 ¹Glass fusion drawn/fictivated and ion exchanged at 410° C. for 8 hours in KNO₃ molten salt bath.

TABLE 2 Compositions and selected physical properties of the glasses described herein that do not contain P₂O₅. Glass (mol %) 1 2 3 4 5 6 SiO₂ 64.05 63.98 64.02 63.96 61.44 62.02 Al₂O₃ 13.59 16.35 15.86 16.41 16.87 16.53 B₂O₃ 8.11 4.00 3.98 2.13 5.40 4.95 Na₂O 13.54 14.40 14.87 16.25 15.59 15.99 K₂O 0.51 1.02 1.02 1.01 0.51 0.51 MgO 0.02 0.02 0.02 0.02 0.02 0.01 CaO 0.07 0.13 0.13 0.13 0.07 0.07 ZnO P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.09 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.46 −0.93 0.02 0.85 −0.77 −0.04 [B₂O₃] − ([Na₂O] + 7.65 4.94 3.96 1.28 6.17 4.99 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 542 623 599 620 600.8 591.3 Anneal Pt. (° C.) 594 684 657 679 659.7 649.2 Soft Pt. (° C.) 856 980 950 969 949 CTE (10⁷° C.⁻¹) 79 84.6 86.3 89.3 Density (g/cm³) 2.368 2.406 2.408 2.433 2.398 E Mod (Mpsi) 9.332 9.871 9.879 G Mod (Mpsi) 3.807 4.044 4.042 ν (Poisson's ratio) 0.226 0.221 0.222 Indentation Threshold (kgf) 40 17.5 17.5 11.5 42.5 27.5 CS (MPa)¹ 945.98 934.91 936.13 CS (MPa)¹ (SOC corrected) 904.22 950.37 DOL (μm)¹ 75.87 74.66 73.94 73.65 72.07 CS (MPa)² 598.55 1025.88 1031.55 1048.43 CS (MPa)² (SOC corrected) 978.33 1069.76 DOL (μm)² 45.97 56.41 57.43 60.06 59.41 56.14 Glass (mol %) 7 8 9 10 11 12 SiO₂ 58.05 59.94 62.02 61.92 64.41 66.99 Al₂O₃ 17.66 16.49 16.53 16.85 14.95 13.31 B₂O₃ 6.08 6.63 5.03 5.04 6.04 5.79 Na₂O 17.49 16.20 15.91 15.67 13.89 13.74 K₂O 0.50 0.51 0.51 0.51 0.52 0.01 MgO 0.02 0.02 0.01 0.02 0.02 0.02 CaO 0.08 0.08 0.07 0.08 0.06 0.02 ZnO P₂O₅ SnO₂ 0.10 0.10 0.09 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.33 0.22 −0.11 −0.66 −0.55 0.44 [B₂O₃] − ([Na₂O] + 5.75 6.41 5.14 5.70 6.59 5.35 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 594 588 591 602.6 603 594 Anneal Pt. (° C.) 648 644 649.4 661.4 662 653 Soft Pt. (° C.) 907 905 946 942 CTE (10⁷° C.⁻¹) 90.8 87.4 80.4 75.3 Density (g/cm³) 2.412 2.399 2.381 2.365 E Mod (Mpsi) 9.52 9.418 9.438 9.309 G Mod (Mpsi) 3.877 3.83 3.865 3.848 ν (Poisson's ratio) 0.228 0.229 0.221 0.21 Indentation Threshold (kgf) 22.5 32.5 27.5 35 50 32.5 CS (MPa)¹ 982.26 887.12 836.34 770.78 CS (MPa)¹ (SOC corrected) 838.10 951.64 992.14 786.73 709.43 DOL (μm)¹ 71.23 70.91 70.87 69.64 69.48 69.26 CS (MPa)² 1134.74 1090.05 940.56 920.95 CS (MPa)² (SOC corrected) 1029.81 1033.00 884.78 847.65 DOL (μm)² 53.67 51.20 58.58 53.11 50.07 Glass (mol %) 13 14 15 16 17 18 SiO₂ 67.14 67.11 60.31 61.66 67.08 66.96 Al₂O₃ 13.21 13.23 16.46 16.22 13.23 13.33 B₂O₃ 5.77 5.76 6.50 5.09 5.77 5.79 Na₂O 13.42 13.42 16.04 16.33 13.46 13.75 K₂O 0.26 0.26 0.51 0.51 0.26 0.01 MgO 0.02 0.02 0.02 0.02 0.02 0.02 CaO 0.05 0.05 0.07 0.07 0.05 0.02 ZnO P₂O₅ SnO₂ 0.10 0.10 0.09 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.47 0.45 0.09 0.62 0.49 0.43 [B₂O₃] − ([Na₂O] + 5.30 5.30 6.41 4.46 5.27 5.36 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 593 592 569.4 569.5 591 594 Anneal Pt. (° C.) 651 650 624.4 622.9 649 652 Soft Pt. (° C.) 931 938 935 942 CTE (10⁷° C.⁻¹) 76.8 76.5 76.3 75.6 Density (g/cm³) 2.369 2.37 2.396 2.408 2.368 2.369 E Mod (Mpsi) 9.412 9.453 9.502 9.34 G Mod (Mpsi) 3.873 3.865 3.845 3.849 ν (Poisson's ratio) 0.215 0.223 0.236 0.213 Indentation Threshold (kgf) 27.5 >25 47.5 17.5 17.5 27.5 CS (MPa)¹ 763.00 767.19 757.38 783.96 CS (MPa)¹ (SOC corrected) 707.18 711.69 833.11 885.94 701.16 726.19 DOL (μm)¹ 69.24 69.17 68.85 68.79 68.70 67.82 CS (MPa)² 901.59 901.02 899.76 928.71 CS (MPa)² (SOC corrected) 835.64 835.84 958.06 1000.30 832.97 860.27 DOL (μm)² 49.25 50.41 54.45 50.89 52.33 48.49 Glass (mol %) 19 20 21 22 23 24 SiO₂ 62.38 67.14 65.66 62.86 57.41 56.99 Al₂O₃ 15.71 13.23 13.71 15.30 19.20 19.12 B₂O₃ 5.05 5.72 6.26 5.14 5.33 5.44 Na₂O 16.17 13.42 13.91 16.01 17.65 17.97 K₂O 0.51 0.26 0.26 0.51 0.25 0.26 MgO 0.02 0.02 0.02 0.02 0.02 0.05 CaO 0.06 0.05 0.05 0.06 0.04 0.06 ZnO 0.00 P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.97 0.45 0.46 1.22 −1.30 −0.89 [B₂O₃] − ([Na₂O] + 4.08 5.26 5.80 3.92 6.63 6.33 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 565 590 586 559.6 627 623 Anneal Pt. (° C.) 617.1 649 644 610.4 683 678 Soft Pt. (° C.) 883.5 936 928 941 928 CTE (10⁷° C.⁻¹) 86.2 76 77.6 88.2 92.6 Density (g/cm³) 2.408 2.367 2.37 2.421 2.426 E Mod (Mpsi) 9.421 9.35 9.705 9.603 G Mod (Mpsi) 3.858 3.828 3.967 3.942 ν (Poisson's ratio) 0.221 0.221 0.223 0.218 Indentation Threshold (kgf) 10 32.5 22.5 10 35 50 CS (MPa)¹ 770.06 775.41 1049.21 1009.69 CS (MPa)¹ (SOC corrected) 819.65 712.06 715.97 787.79 1029.47 999.95 DOL (μm)¹ 67.18 66.93 66.93 66.49 66.43 66.37 CS (MPa)² 893.63 913.97 1211.52 1153.86 CS (MPa) (SOC corrected) 951.03 826.33 843.91 931.00 1188.72 1142.72 DOL (μm)² 53.03 52.27 50.32 50.09 49.38 50.35 Glass (mol %) 25 26 27 28 29 30 SiO₂ 65.34 65.86 64.11 62.89 64.06 65.45 Al₂O₃ 13.84 13.08 14.01 14.67 14.86 13.85 B₂O₃ 6.41 6.96 7.15 6.90 6.01 6.29 Na₂O 14.24 11.72 13.03 14.31 13.81 14.23 K₂O 0.01 2.01 1.50 0.99 1.01 0.01 MgO 0.02 0.02 0.01 0.02 0.02 0.02 CaO 0.02 0.24 0.07 0.11 0.12 0.02 ZnO P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.41 0.66 0.53 0.62 −0.03 0.38 [B₂O₃] − ([Na₂O] + 6.00 6.30 6.62 6.28 6.05 5.91 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 589 540 560 548 570 590 Anneal Pt. (° C.) 646 592 613 599.9 627 646 Soft Pt. (° C.) 928 851 810 920 927 CTE (10⁷° C.⁻¹) 77.8 81.9 82.7 82 78.5 Density (g/cm³) 2.371 2.379 2.382 2.385 2.388 2.372 E Mod (Mpsi) 9.255 9.653 9.467 9.635 9.286 G Mod (Mpsi) 3.812 3.936 3.874 3.913 3.846 v (Poisson's ratio) 0.214 0.226 0.222 0.231 0.207 Indentation Threshold (kgf) 27.5 17.5 47.5 37.5 47.5 37.5 CS (MPa)¹ 792.17 644.93 731.96 844.33 808.31 CS (MPa)¹ (SOC corrected) 728.06 688.85 734.27 746.13 DOL (μm)¹ 66.10 65.87 65.35 65.12 65.00 64.89 CS (MPa)² 920.31 738.35 842.29 935.14 960.00 CS (MPa)² (SOC corrected) 845.84 792.68 844.88 886.15 DOL (μm)² 50.82 52.26 49.62 50.30 49.86 47.59 Glass (mol %) 31 32 33 34 35 36 SiO₂ 64.19 57.07 66.06 65.84 62.87 63.72 Al₂O₃ 15.36 18.78 13.22 13.18 14.96 14.96 B₂O₃ 5.95 5.31 6.98 6.99 6.96 7.05 Na₂O 13.22 18.35 13.04 12.73 14.52 13.57 K₂O 1.02 0.26 0.51 1.01 0.51 0.50 MgO 0.02 0.05 0.02 0.02 0.02 0.02 CaO 0.13 0.05 0.07 0.12 0.07 0.06 ZnO 0.00 P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.09 0.10 [Na₂O] + [K₂O] − [Al₂O₃] −1.12 −0.17 0.33 0.56 0.07 −0.88 [B₂O₃] − ([Na₂O] + 7.07 5.48 6.65 6.43 6.88 7.93 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 586 612 550 545 559.9 592 Anneal Pt. (° C.) 646 667 604 598 615.7 651 Soft Pt. (° C.) 943 921 869 866 933 CTE (10⁷° C.⁻¹) 77.7 94.2 78.4 80.1 78.4 Density (g/cm³) 2.386 2.43 2.372 2.377 2.376 E Mod (Mpsi) 9.572 9.728 9.461 9.55 9.268 G Mod (Mpsi) 3.938 3.928 3.873 3.883 3.806 ν (Poisson's ratio) 0.215 0.238 0.222 0.23 0.218 Indentation Threshold (kgf) 42.5 30 17.5 17.5 42.5 50 CS (MPa)¹ 851.23 954.36 692.07 701.60 809.55 CS (MPa)¹ (SOC corrected) 941.04 779.63 759.29 DOL (μm)¹ 64.72 63.88 63.57 63.16 62.91 62.89 CS (MPa)² 920.57 1152.17 814.65 810.37 919.37 CS (MPa)² (SOC corrected) 1136.09 885.76 862.29 DOL (μm)² 45.33 51.17 48.31 46.04 47.18 47.57 Glass (mol %) 37 38 39 40 41 42 SiO₂ 65.35 63.07 65.83 62.85 65.71 65.86 Al₂O₃ 14.00 15.40 13.59 15.42 13.57 13.56 B₂O₃ 6.11 6.67 5.12 7.02 5.74 5.25 Na₂O 13.84 14.18 14.45 14.02 13.97 14.32 K₂O 0.51 0.51 0.10 0.51 0.10 0.10 MgO 0.01 0.02 0.77 0.02 0.76 0.76 CaO 0.06 0.07 0.05 0.07 0.04 0.04 ZnO 0.00 0.00 0.00 P₂O₅ SnO₂ 0.10 0.09 0.10 0.09 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.34 −0.71 0.96 −0.90 0.51 0.86 [B₂O₃] − ([Na₂O] + 5.76 7.38 4.16 7.92 5.24 4.40 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 580 573.1 584 575.1 586 584 Anneal Pt. (° C.) 636 631.6 638 633.3 641 639 Soft Pt. (° C.) 908 907 915 911 CTE (10⁷° C.⁻¹) 79.5 78.5 76.4 77.7 Density (g/cm³) 2.382 2.39 2.373 2.379 2.388 E Mod (Mpsi) 9.614 9.704 9.558 9.609 G Mod (Mpsi) 3.887 4.007 3.912 3.98 ν (Poisson's ratio) 0.237 0.211 0.222 0.207 Indentation Threshold (kgf) 32.5 47.5 27.5 47.5 32.5 40 CS (MPa)¹ 796.55 809.68 803.88 811.46 CS (MPa)¹ (SOC corrected) 749.86 780.71 784.04 800.99 764.68 778.88 DOL (μm)¹ 62.80 62.50 62.42 62.41 62.01 61.95 CS (MPa)² 911.57 1000.28 946.44 985.28 CS (MPa)² (SOC corrected) 858.13 881.96 968.60 897.79 900.29 945.72 DOL (μm)² 47.90 47.00 44.25 46.57 49.35 45.17 Glass (mol %) 43 44 45 46 47 48 SiO₂ 64.57 64.78 50.50 65.61 65.52 65.74 Al₂O₃ 13.85 13.66 21.09 13.58 13.59 13.57 B₂O₃ 7.04 7.03 7.04 5.59 5.62 5.63 Na₂O 13.84 13.83 20.12 14.21 14.25 14.05 K₂O 0.51 0.51 0.98 0.10 0.10 0.10 MgO 0.02 0.02 0.02 0.76 0.77 0.77 CaO 0.07 0.07 0.13 0.04 0.04 0.04 ZnO 0.00 0.00 0.00 P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.50 0.68 0.01 0.73 0.76 0.58 [B₂O₃] − ([Na₂O] + 6.54 6.35 7.03 4.86 4.85 5.05 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 550 549.5 569 581 581 584 Anneal Pt. (° C.) 603 601.5 620 637 635 639 Soft Pt. (° C.) 867.5 864 906 906 913 CTE (10⁷° C.⁻¹) 77.7 79.3 100.9 77.6 76.7 76.6 Density (g/cm³) 2.38 2.373 2.444 2.385 2.384 2.382 E Mod (Mpsi) 9.506 9.669 9.663 9.608 9.651 G Mod (Mpsi) 3.896 3.906 3.948 3.942 3.92 ν (Poisson's ratio) 0.22 0.238 0.224 0.219 0.231 Indentation Threshold (kgf) 37.5 37.5 12.5 37.5 32.5 40 CS (MPa)¹ 741.35 987.93 802.89 801.35 810.58 CS (MPa)¹ (SOC corrected) 689.48 976.87 766.03 767.10 763.97 DOL (μm)¹ 61.64 61.50 61.36 61.31 61.11 60.80 CS (MPa)² 1137.60 983.29 965.09 971.14 CS (MPa)² (SOC corrected) 775.20 1124.87 938.15 923.84 915.30 DOL (μm)² 50.44 45.76 44.62 46.39 46.48 Glass (mol %) 49 50 51 52 53 54 SiO₂ 65.45 56.88 64.49 59.77 64.44 56.55 Al₂O₃ 13.98 18.36 14.18 16.19 13.99 18.28 B₂O₃ 7.06 5.41 7.02 7.04 7.04 6.55 Na₂O 12.81 18.88 13.61 16.28 13.83 17.37 K₂O 0.50 0.26 0.51 0.51 0.51 0.99 MgO 0.01 0.04 0.01 0.02 0.01 0.02 CaO 0.06 0.06 0.06 0.07 0.06 0.12 ZnO 0.00 0.00 P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] −0.67 0.77 −0.06 0.60 0.35 0.07 [B₂O₃] − ([Na₂O] + 7.73 4.64 7.08 6.44 6.69 6.47 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 588 586 578 552.1 571 562 Anneal Pt. (° C.) 648 640 634 602.8 628 616 Soft Pt. (° C.) 943 892 914 858.6 887 867 CTE (10⁷° C.⁻¹) 75.4 97.2 79.5 79 93.7 Density (g/cm³) 2.363 2.435 2.372 2.399 2.375 2.42 E Mod (Mpsi) 9.182 9.82 9.297 9.333 9.547 G Mod (Mpsi) 3.83 3.975 3.825 3.835 3.871 ν (Poisson's ratio) 0.199 0.235 0.215 0.217 0.233 Indentation Threshold (kgf) 20 12.5 37.5 42.5 37.5 27.5 CS (MPa)¹ 754.06 907.31 795.79 734.76 923.25 CS (MPa)¹ (SOC corrected) 691.64 904.75 741.57 789.38 679.62 899.49 DOL (μm)¹ 60.63 60.58 60.38 60.07 59.90 59.68 CS (MPa)² 865.34 1077.34 906.33 880.03 1042.81 CS (MPa)² (SOC corrected) 793.71 1074.30 844.58 930.97 813.99 1015.97 DOL (μm)² 45.17 46.13 46.55 44.63 46.09 45.26 Glass (mol %) 55 56 57 58 59 60 SiO₂ 57.32 63.79 67.18 64.29 55.42 56.81 Al₂O₃ 19.10 14.44 12.78 13.95 18.46 18.34 B₂O₃ 4.37 5.66 5.65 6.94 7.24 5.64 Na₂O 17.73 15.42 13.70 14.13 18.45 18.74 K₂O 0.25 0.50 0.00 0.51 0.25 0.25 MgO 1.06 0.01 0.54 0.02 0.01 0.04 CaO 0.05 0.06 0.02 0.07 0.05 0.06 ZnO 0.00 0.00 P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] −1.11 1.49 0.92 0.68 0.24 0.66 [B₂O₃] − ([Na₂O] + 5.48 4.17 4.73 6.25 7.00 4.98 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 625 553.3 579 550.4 569 577 Anneal Pt. (° C.) 678 602.1 633 602.9 621 630 Soft Pt. (° C.) 934 904 870.7 858 893 CTE (10⁷° C.⁻¹) 88.7 75.5 79.4 94.3 95.6 Density (g/cm³) 2.438 2.376 2.375 2.424 2.434 E Mod (Mpsi) 9.855 9.547 9.57 9.703 G Mod (Mpsi) 4.018 3.925 3.864 3.98 ν (Poisson's ratio) 0.227 0.216 0.238 0.219 Indentation Threshold (kgf) 15 10 17.5 37.5 32.5 12.5 CS (MPa)¹ 1087.72 747.21 936.43 913.84 CS (MPa)¹ (SOC corrected) 1097.38 745.92 718.15 910.69 DOL (μm)¹ 59.34 59.32 58.98 58.69 58.60 58.58 CS (MPa)² 1214.15 910.00 1081.85 CS (MPa)² (SOC corrected) 1224.94 899.51 805.33 DOL (μm)² 45.38 44.62 42.89 47.80 45.12 Glass (mol %) 61 62 63 64 65 66 SiO₂ 64.36 61.56 63.81 64.14 64.42 57.15 Al₂O₃ 14.49 15.77 14.64 14.77 13.94 18.43 B₂O₃ 7.10 6.04 5.13 7.25 8.06 5.27 Na₂O 13.85 15.91 15.74 13.51 12.87 18.97 K₂O 0.01 0.52 0.50 0.20 0.52 0.01 MgO 0.01 0.02 0.02 0.01 0.01 0.05 CaO 0.06 0.08 0.06 0.03 0.06 0.02 ZnO 0.00 P₂O₅ SnO₂ 0.10 0.10 0.10 0.07 0.10 0.09 [Na₂O] + [K₂O] − [Al₂O₃] −0.63 0.66 1.60 −1.06 −0.55 0.55 [B₂O₃] − ([Na₂O] + 7.73 5.38 3.53 8.31 8.61 4.72 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 591 565 553.8 590 574 580.2195 Anneal Pt. (° C.) 650 617 602.8 648 631 633.1365 Soft Pt. (° C.) 934 888 850 934 916 CTE (10⁷° C.⁻¹) 76.6 88 75.4 75.2 Density (g/cm³) 2.37 2.411 2.408 2.368 2.36 E Mod (Mpsi) 9.315 9.563 9.257 9.148 G Mod (Mpsi) 3.758 3.919 3.803 3.742 ν (Poisson's ratio) 0.239 0.22 0.217 0.222 Indentation Threshold (kgf) 42.5 12.5 10 37.5 20 12.5 CS (MPa)¹ 807.46 926.79 790.43 743.00 971.44 CS (MPa)¹ (SOC corrected) 731.13 758.52 718.78 660.54 965.67 DOL (μm)¹ 58.50 58.25 57.92 57.90 57.68 57.60 CS (MPa)² 917.91 1054.95 930.21 849.33 1097.45 CS (MPa)² (SOC corrected) 831.14 893.72 845.89 755.07 1090.93 DOL (μm)² 43.65 44.97 46.87 43.69 43.40 45.43 Glass (mol %) 67 68 69 70 71 72 SiO₂ 56.23 64.65 62.83 59.76 58.19 56.21 Al₂O₃ 17.64 13.94 14.92 17.11 17.20 18.31 B₂O₃ 8.05 6.98 6.94 5.40 7.06 6.14 Na₂O 16.78 14.20 14.63 17.54 16.29 18.87 K₂O 0.99 0.10 0.51 0.02 0.99 0.26 MgO 0.05 0.01 0.01 0.05 0.02 0.05 CaO 0.14 0.02 0.06 0.03 0.12 0.06 ZnO 0.00 0.00 P₂O₅ SnO₂ 0.10 0.07 0.09 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.13 0.36 0.22 0.45 0.08 0.83 [B₂O₃] − ([Na₂O] + 7.92 6.62 6.72 4.95 6.98 5.31 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 557 571 558.9 579.1148 557 572 Anneal Pt. (° C.) 608 622 613.1 631.8197 610 622 Soft Pt. (° C.) 850 885 866 864 CTE (10⁷° C.⁻¹) 92 79.7 90.5 95.1 Density (g/cm³) 2.411 2.375 2.41 2.432 E Mod (Mpsi) 9.405 9.368 9.489 9.695 G Mod (Mpsi) 3.83 3.814 3.877 3.946 ν (Poisson's ratio) 0.228 0.228 0.224 0.228 Indentation Threshold (kgf) 25 42.5 37.5 27.5 40 15 CS (MPa)¹ 859.86 804.16 929.92 885.30 905.74 CS (MPa)¹ (SOC corrected) 819.03 798.84 914.11 848.48 889.52 DOL (μm)¹ 57.60 57.38 57.26 57.20 57.11 56.82 CS (MPa)² 1035.22 950.12 1059.78 989.53 1074.72 CS (MPa)² (SOC corrected) 986.07 902.29 1041.76 948.37 1055.47 DOL (μm)² 44.40 44.00 42.70 45.24 47.57 44.47 Glass (mol %) 73 74 75 76 77 78 SiO₂ 65.76 64.18 64.53 65.77 57.42 61.99 Al₂O₃ 13.87 14.01 13.99 13.21 18.59 14.65 B₂O₃ 5.15 6.23 6.60 7.04 5.35 6.05 Na₂O 13.91 13.90 13.71 13.84 17.17 14.67 K₂O 0.11 1.49 0.50 0.01 0.26 0.52 MgO 1.08 0.01 0.49 0.01 1.06 0.02 CaO 0.03 0.06 0.06 0.01 0.05 0.08 ZnO 0.00 P₂O₅ SnO₂ 0.07 0.10 0.10 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.15 1.38 0.22 0.65 −1.16 0.55 [B₂O₃] − ([Na₂O] + 5.00 4.86 6.38 6.40 6.51 5.50 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 589 557 570 553 607 610 Anneal Pt. (° C.) 644 607 623 606 661 666 Soft Pt. (° C.) 918 847 890 873 917 919 CTE (10⁷° C.⁻¹) 77.2 84.2 80.4 77.2 86.8 80.5 Density (g/cm³) 2.389 2.402 2.383 2.375 2.429 2.44 E Mod (Mpsi) 9.675 9.809 9.457 9.477 10.009 9.805 G Mod (Mpsi) 3.993 4.044 3.891 3.87 4.1 3.983 ν (Poisson's ratio) 0.212 0.213 0.215 0.225 0.221 0.231 Indentation Threshold (kgf) 50 27.5 32.5 22.5 >25 13.75 CS (MPa)¹ 827.18 722.71 765.12 735.80 1042.17 928.11 CS (MPa)¹ (SOC corrected) 789.68 701.96 718.79 1030.82 DOL (μm)¹ 56.82 56.75 56.73 56.65 56.63 56.53 CS (MPa)² 978.88 863.59 897.56 843.06 1188.56 1121.22 CS (MPa)² (SOC corrected) 934.50 838.80 843.20 1175.63 DOL (μm)² 42.65 46.22 44.17 42.42 43.49 41.84 Glass (mol %) 79 80 81 82 83 84 SiO₂ 54.37 62.36 64.29 60.92 60.08 64.56 Al₂O₃ 19.19 15.59 13.95 16.47 16.62 13.90 B₂O₃ 6.98 5.79 7.65 5.83 6.34 7.03 Na₂O 18.19 16.07 13.90 16.40 16.80 14.31 K₂O 0.99 0.03 0.01 0.07 0.07 0.01 MgO 0.02 0.04 0.01 0.29 0.08 0.01 CaO 0.12 0.02 0.06 0.03 0.03 0.06 ZnO P₂O₅ SnO₂ 0.10 0.10 0.10 0.08 0.08 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.00 0.50 −0.04 0.00 0.25 0.41 [B₂O₃] − ([Na₂O] + 6.99 5.29 7.69 5.83 6.09 6.62 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 561 571.5756 572 573.7447 564.3761 574 Anneal Pt. (° C.) 613 623.9441 629 628.2527 618.0616 627 Soft Pt. (° C.) 862 899 891 CTE (10⁷° C.⁻¹) 96.2 78.5 78.9 Density (g/cm³) 2.428 2.367 2.378 E Mod (Mpsi) 9.573 9.288 9.373 G Mod (Mpsi) 3.896 3.752 3.832 ν (Poisson's ratio) 0.229 0.238 0.223 Indentation Threshold (kgf) 25 37.5 32.5 42.5 37.5 42.5 CS (MPa)¹ 948.59 878.64 774.46 782.10 CS (MPa)¹ (SOC corrected) 929.87 852.11 696.88 903.79 853.09 723.20 DOL (μm)¹ 56.43 55.87 55.70 55.34 55.27 55.22 CS (MPa)² 1072.69 992.79 903.52 918.78 CS (MPa)² (SOC corrected) 1051.53 962.82 813.01 1004.83 974.01 849.58 DOL (μm)² 47.43 43.98 42.06 43.04 44.03 41.80 Glass (mol %) 79 80 81 82 83 84 SiO₂ 54.37 62.36 64.29 60.92 60.08 64.56 Al₂O₃ 19.19 15.59 13.95 16.47 16.62 13.90 B₂O₃ 6.98 5.79 7.65 5.83 6.34 7.03 Na₂O 18.19 16.07 13.90 16.40 16.80 14.31 K₂O 0.99 0.03 0.01 0.07 0.07 0.01 MgO 0.02 0.04 0.01 0.29 0.08 0.01 CaO 0.12 0.02 0.06 0.03 0.03 0.06 ZnO P₂O₅ SnO₂ 0.10 0.10 0.10 0.08 0.08 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.00 0.50 −0.04 0.00 0.25 0.41 [B₂O₃] − ([Na₂O] + 6.99 5.29 7.69 5.83 6.09 6.62 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 561 571.5756 572 573.7447 564.3761 574 Anneal Pt. (° C.) 613 623.9441 629 628.2527 618.0616 627 Soft Pt. (° C.) 862 899 891 CTE (10⁷° C.⁻¹) 96.2 78.5 78.9 Density (g/cm³) 2.428 2.367 2.378 E Mod (Mpsi) 9.573 9.288 9.373 G Mod (Mpsi) 3.896 3.752 3.832 ν (Poisson's ratio) 0.229 0.238 0.223 Indentation Threshold (kgf) 25 37.5 32.5 42.5 37.5 42.5 CS (MPa)¹ 948.59 878.64 774.46 782.10 CS (MPa)¹ (SOC corrected) 929.87 852.11 696.88 903.79 853.09 723.20 DOL (μm)¹ 56.43 55.87 55.70 55.34 55.27 55.22 CS (MPa)² 1072.69 992.79 903.52 918.78 CS (MPa)² (SOC corrected) 1051.53 962.82 813.01 1004.83 974.01 849.58 DOL (μm)² 47.43 43.98 42.06 43.04 44.03 41.80 Glass (mol %) 85 86 87 88 89 90 SiO₂ 55.11 64.31 64.34 64.34 65.71 63.41 Al₂O₃ 18.41 13.68 14.72 14.00 13.90 13.96 B₂O₃ 7.58 7.01 6.18 5.99 5.15 7.07 Na₂O 18.47 14.29 13.43 14.06 13.42 13.89 K₂O 0.25 0.50 0.20 0.51 0.11 1.49 MgO 0.01 0.02 1.01 0.01 1.60 0.01 CaO 0.04 0.06 0.02 0.06 0.04 0.06 ZnO 0.00 0.00 0.91 P₂O₅ SnO₂ 0.10 0.10 0.07 0.10 0.07 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.31 1.11 −1.09 0.57 −0.37 1.42 [B₂O₃] − ([Na₂O] + 7.28 5.90 7.28 5.42 5.52 5.65 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 562 545.1 596 568 594 549 Anneal Pt. (° C.) 611 594.9 653 623 649 596 Soft Pt. (° C.) 857 929 890 928 823 CTE (10⁷° C.⁻¹) 93.2 76 79.8 75.1 86.2 Density (g/cm³) 2.421 2.381 2.404 2.388 2.4 E Mod (Mpsi) 9.468 9.593 9.576 10.005 9.712 G Mod (Mpsi) 3.846 3.91 3.952 4.123 3.993 ν (Poisson's ratio) 0.231 0.227 0.211 0.213 0.216 Indentation Threshold (kgf) 27.5 27.5 32.5 32.5 42.5 27.5 CS (MPa)¹ 871.28 824.73 807.70 826.35 741.59 CS (MPa)¹ (SOC corrected) 715.55 773.18 782.00 788.89 717.44 DOL (μm)¹ 55.06 55.00 54.74 54.74 54.51 54.45 CS (MPa)² 1067.00 960.72 950.41 961.11 847.99 CS (MPa)² (SOC corrected) 855.74 900.68 920.17 917.54 820.39 DOL (μm)² 43.78 41.97 41.27 41.71 40.97 41.98 Glass (mol %) 91 92 93 94 95 96 SiO₂ 60.04 64.59 61.91 64.26 64.77 70.65 Al₂O₃ 16.54 13.88 13.94 13.96 13.87 12.35 B₂O₃ 6.43 7.02 6.07 7.14 6.51 3.95 Na₂O 16.71 13.80 15.46 13.93 14.14 12.35 K₂O 0.07 0.50 0.52 0.52 0.52 0.51 MgO 0.11 0.02 0.02 0.01 0.01 0.02 CaO 0.03 0.06 0.08 0.06 0.06 0.07 ZnO P₂O₅ SnO₂ 0.07 0.10 0.10 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.24 0.41 2.03 0.49 0.78 0.51 [B₂O₃] − ([Na₂O] + 6.19 6.61 4.04 6.65 5.73 3.44 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 566.277 557 593 565 567 582 Anneal Pt. (° C.) 619.0794 610 646 617 617 640 Soft Pt. (° C.) 879 883 885 874 869 949 CTE (10⁷° C.⁻¹) 89.1 79.4 84.4 81 80.5 71.2 Density (g/cm³) 2.399 2.379 2.449 2.379 2.388 2.374 E Mod (Mpsi) 9.607 9.451 9.842 9.443 9.531 9.784 G Mod (Mpsi) 3.925 3.864 4.02 3.858 3.941 4.047 ν (Poisson's ratio) 0.224 0.223 0.224 0.224 0.209 0.209 Indentation Threshold (kgf) 37.5 35 11.75 42.5 37.5 22.5 CS (MPa)¹ 782.47 931.17 786.03 782.17 754.58 CS (MPa)¹ (SOC corrected) 853.81 724.59 737.12 749.86 DOL (μm)¹ 54.45 54.33 54.21 54.15 54.02 53.97 CS (MPa)² 871.70 1147.76 889.71 888.55 861.31 CS (MPa)² (SOC corrected) 971.19 807.23 834.35 851.85 DOL (μm)² 43.91 41.57 39.13 44.73 42.96 49.11 Glass (mol %) 97 98 99 100 101 102 SiO₂ 64.32 62.77 64.75 59.99 54.58 64.48 Al₂O₃ 14.00 14.55 13.91 16.55 18.38 14.03 B₂O₃ 6.15 7.11 7.14 6.44 8.14 5.97 Na₂O 13.82 14.87 13.99 16.85 18.47 13.81 K₂O 0.51 0.51 0.01 0.07 0.26 0.50 MgO 1.01 0.03 0.01 0.07 0.01 1.03 CaO 0.06 0.07 0.06 0.03 0.05 0.07 ZnO 0.00 0.00 P₂O₅ SnO₂ 0.10 0.09 0.10 0.08 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.33 0.82 0.09 0.37 0.34 0.27 [B₂O₃] − ([Na₂O] + 5.83 6.29 7.05 6.07 7.80 5.70 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 572 546.8 577 560.9948 559 572 Anneal Pt. (° C.) 626 597.4 631 613.35 608 625 Soft Pt. (° C.) 889 854.5 913 872.8 846 893 CTE (10⁷° C.⁻¹) 79.4 78.1 89 94.4 79.6 Density (g/cm³) 2.391 2.384 2.371 2.4 2.42 2.389 E Mod (Mpsi) 9.579 9.264 9.56 9.458 9.645 G Mod (Mpsi) 3.955 3.791 3.891 3.836 3.938 ν (Poisson's ratio) 0.211 0.222 0.228 0.233 0.225 Indentation Threshold (kgf) 37.5 32 37.5 42.5 42.5 40 CS (MPa)¹ 769.54 801.86 861.80 830.03 CS (MPa)¹ (SOC corrected) 733.99 748.04 730.95 838.22 799.49 DOL (μm)¹ 53.95 53.90 53.75 53.58 53.55 53.55 CS (MPa)² 905.70 918.13 1080.27 939.81 CS (MPa)² (SOC corrected) 863.86 851.32 836.94 967.98 905.22 DOL (μm)² 40.24 43.64 43.41 42.77 42.36 40.85 Glass (mol %) 103 104 105 106 107 108 SiO₂ 65.01 64.02 64.37 64.27 65.59 65.08 Al₂O₃ 14.23 13.70 13.96 13.94 13.90 13.22 B₂O₃ 5.75 6.96 7.02 7.04 5.12 6.31 Na₂O 14.75 14.63 13.97 13.12 15.15 13.19 K₂O 0.08 0.50 0.01 0.52 0.11 0.51 MgO 0.04 0.02 0.01 0.01 0.01 1.50 CaO 0.03 0.06 0.06 0.06 0.03 0.08 ZnO 0.48 0.92 P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.07 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.60 1.43 0.02 −0.30 1.36 0.48 [B₂O₃] − ([Na₂O] + 5.15 5.53 7.00 7.34 3.76 5.83 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 566.5828 543.7 571 569 571 550 Anneal Pt. (° C.) 620.1886 591.9 627 624 621 603 Soft Pt. (° C.) 895 907 859 CTE (10⁷° C.⁻¹) 76 75.3 82.3 77 Density (g/cm³) 2.389 2.381 2.39 2.403 2.39 E Mod (Mpsi) 9.322 9.46 9.868 9.746 G Mod (Mpsi) 3.814 3.849 4.074 3.99 ν (Poisson's ratio) 0.222 0.229 0.211 0.221 Indentation Threshold (kgf) 37.5 (Ann) 22.5 27.5 32.5 17.5 37.5 CS (MPa)¹ 816.21 809.37 783.77 755.16 751.10 CS (MPa)¹ (SOC corrected) 780.61 706.79 752.35 725.48 737.30 DOL (μm)¹ 53.47 53.29 53.26 53.12 53.06 53.00 CS (MPa)² 930.06 943.17 950.90 CS (MPa)² (SOC corrected) 889.50 827.26 876.73 928.42 DOL (μm)² 42.92 41.77 39.99 41.16 Glass (mol %) 109 110 111 112 113 114 SiO₂ 64.48 63.80 63.21 64.47 66.65 62.81 Al₂O₃ 13.96 13.95 13.99 14.01 13.03 14.61 B₂O₃ 6.04 6.58 8.14 7.01 5.69 6.94 Na₂O 13.21 14.97 13.96 13.78 12.32 14.95 K₂O 0.10 0.50 0.50 0.00 1.01 0.51 MgO 2.10 0.02 0.02 0.53 1.06 0.02 CaO 0.03 0.06 0.06 0.07 0.13 0.06 ZnO 0.00 P₂O₅ SnO₂ 0.07 0.10 0.10 0.10 0.10 0.09 [Na₂O] + [K₂O] − [Al₂O₃] −0.64 1.52 0.47 −0.22 0.30 0.85 [B₂O₃] − ([Na₂O] + 6.69 5.06 7.67 7.24 5.39 6.08 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 583 546 556 574 559.3 548.2 Anneal Pt. (° C.) 637 594 608 630 614.1 598.5 Soft Pt. (° C.) 899 856 906 899.7 CTE (10⁷° C.⁻¹) 74.7 80.6 75.7 75.8 Density (g/cm³) 2.387 2.375 2.372 2.375 E Mod (Mpsi) 9.746 9.276 9.305 G Mod (Mpsi) 3.957 3.807 3.825 ν (Poisson's ratio) 0.232 0.218 0.216 Indentation Threshold (kgf) 42.5 22.5 37.5 42.5 37.5 35 CS (MPa)¹ 811.03 748.11 812.57 CS (MPa)¹ (SOC corrected) 710.94 685.39 757.32 741.11 752.91 DOL (μm)¹ 52.89 52.79 52.77 52.74 52.73 52.66 CS (MPa)² 953.71 876.23 926.46 CS (MPa)² (SOC corrected) 833.02 802.77 863.47 804.99 856.01 DOL (μm)² 37.37 45.00 41.62 41.21 43.35 44.04 Glass (mol %) 115 116 117 118 119 120 SiO₂ 53.46 64.53 64.76 64.21 65.13 66.06 Al₂O₃ 18.42 13.91 13.97 14.68 13.10 13.66 B₂O₃ 9.13 6.61 5.57 5.73 6.07 5.74 Na₂O 18.56 13.72 13.56 13.51 12.97 14.29 K₂O 0.26 0.10 0.50 0.20 0.51 0.07 MgO 0.01 1.02 1.45 1.54 2.03 0.04 CaO 0.05 0.02 0.06 0.03 0.08 0.03 ZnO 0.00 0.00 0.00 0.00 P₂O₅ SnO₂ 0.10 0.07 0.10 0.07 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.39 −0.09 0.09 −0.97 0.38 0.70 [B₂O₃] − ([Na₂O] + 8.74 6.70 5.48 6.71 5.70 5.04 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 556 578 577 598 553 563.1957 Anneal Pt. (° C.) 606 632 632 654 606 616.3392 Soft Pt. (° C.) 828 906 895 926 CTE (10⁷° C.⁻¹) 93.1 76.6 79 76.8 76.7 Density (g/cm³) 2.414 2.38 2.395 2.388 2.391 E Mod (Mpsi) 9.292 9.544 9.605 9.664 9.822 G Mod (Mpsi) 3.767 3.902 4.006 3.975 4.02 ν (Poisson's ratio) 0.233 0.223 0.199 0.215 0.222 Indentation Threshold (kgf) 42.5 47.5 42.5 37.5 37.5 37.5 (Ann) CS (MPa)¹ 824.51 820.08 791.46 840.55 740.40 789.01 CS (MPa)¹ (SOC corrected) 762.22 795.76 753.01 DOL (μm)¹ 52.65 52.62 52.57 52.47 52.47 51.98 CS (MPa)² 1001.44 966.08 900.76 974.09 905.41 CS (MPa)² (SOC corrected) 867.48 922.18 864.11 DOL (μm)² 41.74 40.47 41.52 40.15 41.55 Glass (mol %) 121 122 123 124 125 126 SiO₂ 67.63 62.14 64.53 66.44 66.45 66.42 Al₂O₃ 12.84 15.58 13.98 13.46 13.10 13.04 B₂O₃ 6.03 5.50 5.06 5.15 5.11 5.11 Na₂O 12.81 15.76 13.74 12.63 13.00 13.10 K₂O 0.51 0.06 0.51 0.20 0.20 0.20 MgO 0.01 0.92 2.00 2.01 2.01 2.01 CaO 0.07 0.04 0.06 0.03 0.03 0.03 ZnO 0.00 0.00 0.00 0.00 P₂O₅ SnO₂ 0.10 0.08 0.10 0.07 0.07 0.07 [Na₂O] + [K₂O] − [Al₂O₃] 0.48 0.24 0.28 −0.63 0.10 0.26 [B₂O₃] − ([Na₂O] + 5.54 5.25 4.78 5.78 5.01 4.85 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 558 567.7924 581 597 587 585 Anneal Pt. (° C.) 612 620.85 634 654 642 639 Soft Pt. (° C.) 888 885 902 927 911 909 CTE (10⁷° C.⁻¹) 76.7 84.8 79.7 73.2 75 75.9 Density (g/cm³) 2.374 2.401 2.383 2.386 2.387 E Mod (Mpsi) 9.544 9.703 9.776 9.698 9.764 9.799 G Mod (Mpsi) 3.942 3.967 4.042 4.038 4.013 4.029 ν (Poisson's ratio) 0.211 0.223 0.209 0.201 0.216 0.216 Indentation Threshold (kgf) 17.5 37.5 35 35 40 40 CS (MPa)¹ 804.54 796.84 807.95 802.46 799.16 CS (MPa)¹ (SOC corrected) 869.82 776.81 772.02 766.77 764.54 DOL (μm)¹ 51.82 51.71 51.63 51.59 51.59 51.32 CS (MPa)² 873.09 914.88 926.42 935.89 936.31 CS (MPa)² (SOC corrected) 978.41 891.88 885.22 894.27 895.75 DOL (μm)² 42.02 40.62 40.07 39.96 39.90 40.19 Glass (mol %) 127 128 129 130 131 132 SiO₂ 65.17 64.57 65.24 66.44 64.33 67.77 Al₂O₃ 13.40 14.03 12.91 13.69 14.01 13.01 B₂O₃ 6.56 7.00 5.47 5.15 4.58 3.49 Na₂O 12.77 12.71 12.67 12.37 13.82 12.74 K₂O 1.01 0.49 0.51 0.20 0.51 0.10 MgO 0.87 1.01 3.01 2.03 2.57 2.76 CaO 0.12 0.07 0.09 0.02 0.06 0.04 ZnO 0.00 0.00 P₂O₅ SnO₂ 0.10 0.10 0.10 0.07 0.10 0.07 [Na₂O] + [K₂O] − [Al₂O₃] 0.38 −0.83 0.27 −1.12 0.33 −0.17 [B₂O₃] − ([Na₂O] + 6.17 7.83 5.20 6.28 4.24 3.66 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 549.7 576 561 604 588 604 Anneal Pt. (° C.) 603.3 631 613 661 640 660 Soft Pt. (° C.) 878.4 913 939 899 942 CTE (10⁷° C.⁻¹) 74.9 74.7 71.2 78.2 73.9 Density (g/cm³) 2.375 2.372 2.397 2.382 2.407 2.393 E Mod (Mpsi) 9.425 9.964 9.803 9.885 9.945 G Mod (Mpsi) 3.851 4.077 4.038 4.089 4.118 ν (Poisson's ratio) 0.224 0.222 0.214 0.209 0.208 Indentation Threshold (kgf) 37.5 35 37.5 42.5 35 22.5 CS (MPa)¹ 792.11 732.63 801.36 806.89 825.18 CS (MPa)¹ (SOC corrected) 712.77 728.85 710.62 762.74 794.90 811.15 DOL (μm)¹ 51.27 51.08 51.03 50.74 50.41 50.38 CS (MPa)² 899.49 920.82 928.73 940.49 CS (MPa)² (SOC corrected) 789.12 827.65 876.44 914.92 924.50 DOL (μm)² 39.35 40.29 38.95 39.34 38.92 Glass (mol %) 133 134 135 136 137 138 SiO₂ 64.46 56.17 63.39 65.74 63.39 65.08 Al₂O₃ 13.96 16.64 14.00 13.87 14.04 12.96 B₂O₃ 6.01 10.14 6.91 5.08 7.02 5.78 Na₂O 14.86 15.77 14.08 12.94 13.84 13.00 K₂O 0.51 0.98 0.51 0.11 0.50 0.51 MgO 0.01 0.05 0.01 2.13 1.03 2.49 CaO 0.06 0.13 0.06 0.04 0.07 0.09 ZnO 0.92 P₂O₅ SnO₂ 0.10 0.10 0.10 0.07 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 1.42 0.12 0.60 −0.82 0.29 0.55 [B₂O₃] − ([Na₂O] + 4.59 10.02 6.31 5.90 6.73 5.23 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 562 535 555 597 562 554 Anneal Pt. (° C.) 611 584 606 653 614 607 Soft Pt. (° C.) 852 821 861 928 875 CTE (10⁷° C.⁻¹) 82.4 89.1 79.5 72.3 80.8 76.8 Density (g/cm³) 2.404 2.392 2.401 2.388 2.384 2.396 E Mod (Mpsi) 9.812 9.233 9.497 9.835 9.546 9.897 G Mod (Mpsi) 4.033 3.72 3.903 4.033 3.897 4.051 ν (Poisson's ratio) 0.216 0.241 0.217 0.219 0.225 0.222 Indentation Threshold (kgf) 17.5 27.5 32.5 32.5 42.5 37.5 CS (MPa)¹ 769.17 753.37 789.68 815.47 801.66 752.16 CS (MPa)¹ (SOC corrected) 750.06 697.75 758.32 779.91 773.92 730.45 DOL¹ (μm) 50.34 50.19 50.06 49.91 49.66 49.62 CS (MPa)² 905.17 926.36 930.69 931.65 927.02 CS (MPa)² (SOC corrected) 882.69 857.96 893.73 891.02 894.94 DOL (μm)² 39.37 39.87 38.28 38.80 38.61 Glass (mol %) 139 140 141 142 143 144 SiO₂ 64.85 61.79 64.05 62.84 62.54 65.69 Al₂O₃ 13.01 16.47 14.24 13.97 13.89 13.68 B₂O₃ 6.81 5.04 5.91 8.37 8.83 6.28 Na₂O 13.09 16.00 12.00 11.12 11.06 13.90 K₂O 0.51 0.51 3.32 3.23 3.22 0.25 MgO 1.53 0.02 0.02 0.02 0.02 0.02 CaO 0.08 0.07 0.36 0.35 0.35 0.05 ZnO P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.59 0.04 1.08 0.39 0.38 0.47 [B₂O₃] − ([Na₂O] + 6.22 4.99 4.83 7.99 8.44 5.81 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 547 586.1 542 525 521 585 Anneal Pt. (° C.) 599 643.6 593 578 573 641 Soft Pt. (° C.) 857 926.5 841 834 826 925 CTE (10⁷° C.⁻¹) 76.4 88 85.2 83.6 78.4 Density (g/cm³) 2.388 2.401 2.408 2.38 2.377 2.372 E Mod (Mpsi) 9.712 9.876 9.389 9.349 9.369 G Mod (Mpsi) 3.981 4.074 3.848 3.768 3.854 ν (Poisson's ratio) 0.22 0.212 0.22 0.241 0.216 Indentation Threshold (kgf) 37.5 22.5 22.5 (Ann) 22.5 (Ann) 27.5 (Ann) 37.5 CS (MPa)¹ 722.07 CS (MPa)¹ (SOC corrected) DOL (μm)¹ 49.44 CS (MPa)² 849.69 801.14 703.76 693.72 930.58 CS (MPa)² (SOC corrected) 981.12 859.49 DOL (μm)² 36.69 62.27 54.02 53.07 50.85 49.26 Glass (mol %) 145 146 147 148 149 150 SiO₂ 62.21 63.18 61.99 62.37 63.24 62.10 Al₂O₃ 13.82 13.45 13.78 13.86 13.45 13.48 B₂O₃ 9.32 9.03 8.87 8.33 8.93 9.99 Na₂O 11.00 13.23 11.71 11.75 13.26 13.31 K₂O 3.20 0.94 3.19 3.21 0.94 0.95 MgO 0.01 0.01 0.02 0.02 0.01 0.01 CaO 0.34 0.02 0.34 0.34 0.02 0.02 ZnO P₂O₅ SnO₂ 0.10 0.11 0.10 0.10 0.12 0.12 [Na₂O] + [K₂O] − [Al₂O₃] 0.38 0.71 1.13 1.11 0.76 0.78 [B₂O₃] − ([Na₂O] + 8.95 8.32 7.74 7.23 8.17 9.21 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 518 548 518 523 550 Anneal Pt. (° C.) 570 601 566 571 602 Soft Pt. (° C.) 824 850 797 808 841 CTE (10⁷° C.⁻¹) 84 79.7 85.6 85.2 79.6 Density (g/cm³) 2.374 2.359 2.389 2.393 2.363 E Mod (Mpsi) 9.245 9.14 9.524 9.596 G Mod (Mpsi) 3.799 3.736 3.902 3.935 ν (Poisson's ratio) 0.217 0.223 0.221 0.219 Indentation Threshold (kgf) 32.5 (Ann) 32 (Ann) 22.5 (Ann) 17.5 (Ann) 35 (Ann) 32.5 (Ann) CS (MPa)¹ CS (MPa)¹ (SOC corrected) DOL (μm)¹ CS (MPa)² 688.61 861.02 719.85 726.49 865.32 820.65 CS (MPa)² (SOC corrected) 784.54 788.46 DOL (μm)² 48.85 48.13 47.96 47.80 47.30 47.09 Glass (mol %) 151 152 153 154 155 156 SiO₂ 62.70 64.44 68.60 64.26 64.88 64.24 Al₂O₃ 13.94 12.27 12.86 12.73 13.71 12.45 B₂O₃ 7.89 10.01 5.08 8.97 7.98 9.47 Na₂O 11.79 12.16 12.75 12.93 12.27 12.73 K₂O 3.21 0.95 0.52 0.94 1.02 0.94 MgO 0.02 0.01 0.01 0.01 0.01 0.01 CaO 0.35 0.02 0.07 0.02 0.01 0.02 ZnO P₂O₅ SnO₂ 0.10 0.12 0.10 0.12 0.12 0.12 [Na₂O] + [K₂O] − [Al₂O₃] 1.05 0.84 0.41 1.14 −0.43 1.22 [B₂O₃] − ([Na₂O] + 6.84 9.17 4.67 7.84 8.40 8.25 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 531 536 571 543 550 540 Anneal Pt. (° C.) 579 588 628 594 609 589 Soft Pt. (° C.) 808 835 917 833 897 828 CTE (10⁷° C.⁻¹) 86.9 78 75.7 76.1 77.6 Density (g/cm³) 2.396 2.346 2.377 2.363 2.361 2.358 E Mod (Mpsi) 9.678 8.982 9.654 9.22 9.14 G Mod (Mpsi) 3.971 3.69 3.987 3.781 3.767 ν (Poisson's ratio) 0.219 0.217 0.211 0.219 0.213 Indentation Threshold (kgf) 22.5 32.5 32.5 32.5 32.5 32.5 CS (MPa)¹ 762.53 CS (MPa)¹ (SOC corrected) DOL (μm)¹ 48.26 CS (MPa)² 760.22 715.21 880.90 820.69 774.93 789.60 CS (MPa)² (SOC corrected) DOL (μm)² 47.06 46.76 46.44 46.23 46.10 45.68 Glass (mol %) 157 158 159 160 161 162 SiO₂ 51.33 62.37 62.08 55.91 64.96 62.21 Al₂O₃ 20.21 13.46 14.39 18.37 14.21 14.18 B₂O₃ 7.03 9.78 9.02 6.62 6.97 8.97 Na₂O 19.17 13.26 13.37 18.66 12.72 13.51 K₂O 0.97 0.95 1.02 0.26 0.98 1.01 MgO 1.03 0.01 0.00 0.02 0.01 0.01 CaO 0.13 0.02 0.02 0.05 0.01 0.02 ZnO 0.00 P₂O₅ SnO₂ 0.10 0.12 0.10 0.10 0.12 0.10 [Na₂O] + [K₂O] − [Al₂O₃] −0.07 0.74 0.00 0.55 −0.50 0.33 [B₂O₃] − ([Na₂O] + 7.10 9.04 9.02 6.07 7.47 8.64 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 564 540 538 575 567 532 Anneal Pt. (° C.) 615 593 593 626 627 584 Soft Pt. (° C.) 851 840 868 866 921 841 CTE (10⁷° C.⁻¹) 97.2 80.6 81.2 91.5 77.6 82.2 Density (g/cm³) 2.443 2.359 2.367 2.427 2.371 2.365 E Mod (Mpsi) 9.786 9.116 9.557 9.354 9.282 G Mod (Mpsi) 3.945 3.727 3.903 3.854 3.761 ν (Poisson's ratio) 0.24 0.223 0.224 0.214 0.234 Indentation Threshold (kgf) 12.5 32.5 32.5 32.5 32.5 32.5 CS (MPa)¹ 1020.56 CS (MPa)¹ (SOC corrected) 977.84 DOL (μm)¹ 49.18 CS (MPa)² 1083.22 834.56 809.46 1069.90 934.83 792.98 CS (MPa)² (SOC corrected) 1037.89 DOL (μm)² 45.55 45.52 45.37 45.24 45.19 44.83 Glass (mol %) 163 164 165 166 167 168 SiO₂ 61.74 65.30 62.13 64.46 65.29 62.12 Al₂O₃ 13.71 13.87 14.33 13.94 13.96 13.92 B₂O₃ 9.29 6.25 8.13 6.97 6.25 9.02 Na₂O 11.63 13.83 14.32 13.87 14.00 13.81 K₂O 3.17 0.50 0.98 0.51 0.24 1.00 MgO 0.02 0.01 0.01 0.01 0.01 0.01 CaO 0.34 0.07 0.02 0.06 0.06 0.02 ZnO P₂O₅ SnO₂ 0.10 0.12 0.10 0.12 0.12 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 1.09 0.46 0.97 0.44 0.29 0.89 [B₂O₃] − ([Na₂O] + 8.19 5.79 7.16 6.54 5.96 8.13 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 514 574 536 566 579 530 Anneal Pt. (° C.) 563 628 585 620 635 581 Soft Pt. (° C.) 789 894 827 893 908 824 CTE (10⁷° C.⁻¹) 84.4 79.2 84.2 79.8 78.7 82.4 Density (g/cm³) 2.386 2.384 2.39 2.379 2.381 2.377 E Mod (Mpsi) 9.486 9.556 9.495 9.454 9.463 9.381 G Mod (Mpsi) 3.881 3.906 3.902 3.843 3.873 3.81 ν (Poisson's ratio) 0.222 0.223 0.217 0.23 0.222 0.231 Indentation Threshold (kgf) 22.5 32.5 32.5 32.5 32.5 32.5 CS (MPa)¹ CS (MPa)¹ (SOC corrected) DOL (μm)¹ CS (MPa)² 704.31 934.16 845.92 915.32 946.70 805.04 CS (MPa)² (SOC corrected) 875.26 859.38 875.65 DOL (μm)² 44.05 43.95 43.71 43.15 42.95 42.68 Glass (mol %) 169 170 171 172 173 174 SiO₂ 62.09 64.23 65.29 62.19 62.83 64.24 Al₂O₃ 14.10 12.01 13.88 13.85 13.16 12.46 B₂O₃ 8.59 10.01 6.24 9.00 9.92 9.44 Na₂O 14.09 11.70 14.07 13.81 12.98 12.74 K₂O 1.01 1.91 0.26 1.02 0.99 0.94 MgO 0.01 0.00 0.01 0.01 0.00 0.01 CaO 0.02 0.02 0.06 0.02 0.02 0.02 ZnO P₂O₅ SnO₂ 0.10 0.12 0.12 0.10 0.10 0.12 [Na₂O] + [K₂O] − [Al₂O₃] 1.01 1.60 0.45 0.97 0.81 1.22 [B₂O₃] − ([Na₂O] + 7.58 8.41 5.79 8.03 9.11 8.22 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 529 514 576 526 520 Anneal Pt. (° C.) 578 561 630 575 570 Soft Pt. (° C.) 808 783 897 816 808 CTE (10⁷° C.⁻¹) 83.4 77.5 79.5 83 79.2 Density (g/cm³) 2.387 2.367 2.383 2.379 2.363 E Mod (Mpsi) 9.436 9.365 9.425 9.319 9.202 G Mod (Mpsi) 3.884 3.833 3.931 3.838 3.742 ν (Poisson's ratio) 0.215 0.222 0.199 0.214 0.23 Indentation Threshold (kgf) 32.5 32.5 32.5 32.5 32.5 32.5 CS (MPa)¹ CS (MPa)¹ (SOC corrected) DOL (μm)¹ CS (MPa)² 816.97 649.74 945.67 786.16 717.94 818.76 CS (MPa)² (SOC corrected) 883.18 DOL (μm)² 42.18 42.17 41.94 41.82 41.74 41.73 Glass (mol %) 175 176 177 178 179 180 SiO₂ 64.38 63.93 65.07 66.09 64.40 64.14 Al₂O₃ 12.02 13.83 13.92 13.08 13.44 13.42 B₂O₃ 9.80 8.09 6.31 6.97 8.95 7.15 Na₂O 12.69 13.44 14.45 13.17 12.13 14.11 K₂O 0.93 0.51 0.01 0.51 0.96 1.04 MgO 0.01 0.02 0.01 0.01 0.00 0.00 CaO 0.02 0.07 0.06 0.07 0.01 0.02 ZnO P₂O₅ SnO₂ 0.12 0.10 0.12 0.10 0.10 0.12 [Na₂O] + [K₂O] − [Al₂O₃] 1.60 0.12 0.54 0.61 −0.35 1.74 [B₂O₃] − ([Na₂O] + 8.21 7.97 5.78 6.37 9.30 5.41 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 535 541 576 551 539 539 Anneal Pt. (° C.) 583 597 629 605 595 586 Soft Pt. (° C.) 807 881 894 879 878 810 CTE (10⁷° C.⁻¹) 78.5 78.4 77.9 73.5 82.1 Density (g/cm³) 2.36 2.368 2.385 2.373 2.354 2.398 E Mod (Mpsi) 9.257 9.257 9.432 9.46 9.027 9.836 G Mod (Mpsi) 3.799 3.777 3.887 3.874 3.725 4.031 ν (Poisson's ratio) 0.219 0.225 0.213 0.221 0.212 0.22 Indentation Threshold (kgf) 32.5 (Ann) >25 32.5 22.5 35 (Ann) 17.5 (Ann) CS (MPa)¹ CS (MPa)¹ (SOC corrected) DOL (μm)¹ CS (MPa)² 788.63 863.11 955.90 862.03 763.13 836.58 CS (MPa)² (SOC corrected) 888.56 DOL (μm)² 41.43 41.31 41.12 41.12 40.69 40.65 Glass (mol %) 181 182 183 184 185 186 SiO₂ 62.13 61.38 64.41 64.67 60.98 65.38 Al₂O₃ 13.59 13.64 12.94 13.50 13.80 12.94 B₂O₃ 9.50 9.79 10.07 8.97 10.16 7.10 Na₂O 13.64 11.58 11.38 12.73 13.92 13.88 K₂O 1.01 3.15 1.04 0.02 1.01 0.51 MgO 0.00 0.02 0.01 0.01 0.01 0.01 CaO 0.02 0.34 0.03 0.01 0.02 0.06 ZnO P₂O₅ SnO₂ 0.10 0.10 0.12 0.08 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 1.06 1.09 −0.52 −0.75 1.13 1.44 [B₂O₃] − ([Na₂O] + 8.44 8.70 10.59 9.72 9.04 5.66 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 522 512 529 569 517 554 Anneal Pt. (° C.) 571 560 586 628 565 602 Soft Pt. (° C.) 799 792 876 909 786 836 CTE (10⁷° C.⁻¹) 81.8 85.3 73.9 69.8 83.9 79.3 Density (g/cm³) 2.375 2.384 2.343 2.345 2.375 2.388 E Mod (Mpsi) 9.319 9.472 8.962 9.01 9.32 9.677 G Mod (Mpsi) 3.819 3.859 3.658 3.697 3.804 3.981 ν (Poisson's ratio) 0.22 0.227 0.225 0.219 0.225 0.215 Indentation Threshold (kgf) 32.5 32.5 32.5 32.5 22.5 25 CS (MPa)¹ 729.73 CS (MPa)¹ (SOC corrected) 695.30 DOL (μm)¹ 48.21 CS (MPa)² 742.96 716.14 684.53 808.33 757.92 857.10 CS (MPa)² (SOC corrected) 816.65 DOL (μm)² 40.65 40.59 40.52 40.46 39.98 39.86 Glass (mol %) 187 188 189 190 191 192 SiO₂ 64.48 64.56 62.26 65.09 61.29 64.50 Al₂O₃ 12.48 13.14 13.68 13.81 13.54 13.00 B₂O₃ 10.05 9.02 8.99 6.24 10.24 7.98 Na₂O 11.81 12.05 13.95 14.60 13.73 13.39 K₂O 1.03 1.09 1.00 0.01 1.07 0.99 MgO 0.01 0.01 0.00 0.01 0.01 0.01 CaO 0.02 0.01 0.02 0.06 0.02 0.01 ZnO P₂O₅ SnO₂ 0.12 0.12 0.10 0.12 0.10 0.12 [Na₂O] + [K₂O] − [Al₂O₃] 0.37 0.01 1.26 0.80 1.26 1.37 [B₂O₃] − ([Na₂O] + 9.68 9.01 7.73 5.44 8.98 6.61 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 522 530 527 570 518 533 Anneal Pt. (° C.) 576 586 574 621 566 582 Soft Pt. (° C.) 835 867 803 879 780 819 CTE (10⁷° C.⁻¹) 75.5 76.6 82.2 78.8 82.1 79.7 Density (g/cm³) 2.349 2.355 2.383 2.388 2.378 2.383 E Mod (Mpsi) 9.007 9.09 9.621 9.355 9.342 9.568 G Mod (Mpsi) 3.713 3.742 3.868 3.857 3.809 3.949 ν (Poisson's ratio) 0.213 0.215 0.244 0.213 0.226 0.211 Indentation Threshold (kgf) 32.5 32.5 17.5 32.5 32.5 17 CS (MPa)¹ CS (MPa)¹ (SOC corrected) DOL (μm)¹ CS (MPa)² 683.02 755.13 799.44 946.67 746.92 792.49 CS (MPa)² (SOC corrected) 872.33 DOL (μm)² 39.53 39.51 39.43 39.31 38.99 38.97 Glass (mol %) 193 194 195 196 197 198 SiO₂ 65.43 64.11 64.72 62.40 67.63 61.87 Al₂O₃ 13.23 14.71 13.33 13.17 13.22 13.30 B₂O₃ 5.91 5.22 8.00 10.40 3.45 10.22 Na₂O 12.33 13.55 13.26 12.90 12.61 13.46 K₂O 1.01 0.20 0.51 0.99 0.10 1.04 MgO 2.13 2.10 0.01 0.01 2.87 0.01 CaO 0.14 0.03 0.07 0.02 0.04 0.02 ZnO 0.00 P₂O₅ SnO₂ 0.10 0.07 0.10 0.10 0.07 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.12 −0.96 0.44 0.72 −0.52 1.20 [B₂O₃] − ([Na₂O] + 5.79 6.18 7.56 9.68 3.96 9.02 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 557.1 598 539 518 610 517 Anneal Pt. (° C.) 610.8 652 590 568 665 566 Soft Pt. (° C.) 922 861 798 935 787 CTE (10⁷° C.⁻¹) 76.7 79.3 77.5 71.2 81.5 Density (g/cm³) 2.396 2.37 2.361 2.392 2.373 E Mod (Mpsi) 9.861 9.329 9.119 9.969 9.34 G Mod (Mpsi) 4.031 3.819 3.722 4.142 3.799 ν (Poisson's ratio) 0.223 0.221 0.225 0.203 0.229 Indentation Threshold (kgf) 32.5 47.5 17.5 32.5 22.5 32.5 CS (MPa)¹ 859.15 829.12 CS (MPa)¹(SOC corrected) 739.27 829.92 815.28 DOL (μm)¹ 48.95 47.87 49.41 CS (MPa)² 985.85 862.47 722.43 937.28 753.27 CS (MPa)² (SOC corrected) 790.05 952.31 921.63 DOL (μm)² 38.96 38.91 38.86 38.76 38.73 38.71 Glass (mol %) 199 200 201 202 203 204 SiO₂ 61.93 64.35 64.46 63.06 66.86 63.31 Al₂O₃ 13.32 13.43 12.99 12.87 13.54 14.01 B₂O₃ 10.21 8.44 7.12 10.01 3.41 7.11 Na₂O 13.39 13.63 13.76 12.91 13.47 14.87 K₂O 1.03 0.02 1.48 1.02 0.00 0.51 MgO 0.00 0.01 0.01 0.01 2.57 0.01 CaO 0.02 0.01 0.06 0.02 0.04 0.06 ZnO P₂O₅ SnO₂ 0.10 0.10 0.10 0.10 0.08 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 1.10 0.21 2.25 1.07 −0.07 1.37 [B₂O₃] − ([Na₂O] + 9.12 8.23 4.87 8.94 3.47 5.74 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 518 547 544 517 596.8418 557 Anneal Pt. (° C.) 566 600 590 567 651.925 604 Soft Pt. (° C.) 815 867 803 796 930 838 CTE (10⁷° C.⁻¹) 81.5 75.7 83.4 79.7 74.4 82.8 Density (g/cm³) 2.372 2.362 2.405 2.364 2.397 E Mod (Mpsi) 9.252 9.09 9.882 9.261 10.046 9.668 G Mod (Mpsi) 3.787 3.767 4.092 3.781 4.115 3.962 ν (Poisson's ratio) 0.222 0.207 0.208 0.225 0.221 0.22 Indentation Threshold (kgf) 32.5 33.5 22.5 32.5 17.5 17.5 CS (MPa)¹ 675.85 758.41 CS (MPa)¹ (SOC corrected) 663.13 873.85 735.51 DOL (μm)¹ 47.67 47.97 47.46 CS (MPa)² 735.23 850.10 812.89 739.90 905.98 CS (MPa)² (SOC corrected) 797.59 951.73 878.63 DOL (μm)² 38.58 38.51 38.48 38.47 38.37 38.19 Glass (mol %) 205 206 207 208 209 210 SiO₂ 64.19 63.98 68.73 67.78 67.53 57.08 Al₂O₃ 12.66 14.65 13.23 13.46 13.77 18.53 B₂O₃ 10.08 4.65 3.44 3.46 3.43 4.99 Na₂O 11.86 13.71 12.01 12.28 12.68 18.69 K₂O 1.05 0.21 0.00 0.10 0.00 0.49 MgO 0.01 2.68 2.46 2.79 2.47 0.01 CaO 0.02 0.03 0.04 0.04 0.04 0.07 ZnO 0.00 P₂O₅ SnO₂ 0.12 0.07 0.06 0.07 0.07 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.26 −0.73 −1.22 −1.09 −1.09 0.65 [B₂O₃] − ([Na₂O] + 9.82 5.38 4.66 4.55 4.52 4.34 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 522 602 611.8241 618 609.9735 599 Anneal Pt. (° C.) 576 656 669.7462 674 667.3236 654 Soft Pt. (° C.) 846 917 961 952 961.4 922 CTE (10⁷° C.⁻¹) 75.3 76.7 69.4 70.6 72 95.3 Density (g/cm³) 2.346 2.403 2.391 2.388 2.429 E Mod (Mpsi) 8.96 9.998 10.076 10.021 10.04 9.774 G Mod (Mpsi) 3.691 4.087 4.154 4.136 4.161 3.949 ν (Poisson's ratio) 0.214 0.223 0.213 0.211 0.206 0.237 Indentation Threshold (kgf) 32.5 42.5 32.5 22.5 32.5 12.5 CS (MPa)¹ 871.17 826.03 CS (MPa)¹ (SOC corrected) 854.51 794.15 808.24 842.19 DOL (μm)¹ 48.40 46.13 47.58 47.27 CS (MPa)² 716.98 996.31 922.73 CS (MPa)² (SOC corrected) 977.26 865.74 902.86 915.68 DOL (μm) ² 38.18 38.17 38.04 38.02 38.01 Glass (mol %) 211 212 213 214 215 216 217 SiO₂ 57.03 57.09 61.20 61.13 60.43 59.37 58.52 Al₂O₃ 18.70 18.63 16.86 16.99 17.36 17.50 17.52 B₂O₃ 5.03 5.09 5.16 5.10 5.06 5.78 6.63 Na₂O 18.52 18.47 15.22 14.52 14.45 14.42 14.39 K₂O 0.49 0.49 1.42 2.19 2.65 2.88 2.89 MgO 0.02 0.02 0.11 0.03 0.01 0.01 0.01 CaO 0.07 0.08 0.02 0.02 0.02 0.02 0.02 ZnO P₂O₅ SnO₂ 0.10 0.10 [Na₂O] + [K₂O] − [Al₂O₃] 0.31 0.34 −0.22 −0.27 −0.26 −0.19 −0.23 [B₂O₃] − ([Na₂O] + 4.72 4.75 5.37 5.37 5.32 5.97 6.87 [K₂O] − [Al₂O₃]) Strain Pt. (° C.) 612 609 596 594 595 585 572 Anneal Pt. (° C.) 667 664 654 654 654 641 629 Soft Pt. (° C.) 927 928 940.1 943.9 940.9 927.1 911.7 CTE (10⁷° C.⁻¹) 94.5 87.7 90 92.3 93.5 93.8 Density (g/cm³) 2.426 2.427 2.412 2.412 2.415 2.414 2.41 E Mod (Mpsi) 9.683 9.687 9.807 9.616 9.664 9.693 9.631 G Mod (Mpsi) 3.935 3.964 3.984 4.016 4.007 3.932 3.878 ν (Poisson's ratio) 0.23 0.222 0.231 0.197 0.206 0.233 0.242 Indentation Threshold (kgf) 20 25 27.5 27.5 27.5 32.5 27.5 CS (MPa)¹ CS (MPa)¹ (SOC corrected) DOL (μm)¹ CS (MPa)² CS (MPa)² (SOC corrected) 1122.4 (16 hr) 1093.3 (16 hr) 1125.70 1102.90 1066.30 DOL (μm)² 77.1 (16 hr) 83.4 (16 hr) 61.50 60.50 56.40 ¹Glass is fusion drawn/fictivated and ion exchanged at 410° C. for 8 hours in KNO₃ molten salt bath. ²Glass annealed and ion exchanged at 410° C. for 8 hours in KNO₃ molten salt bath.

In a first aspect a glass comprises: from about 50 mol % to about 72 mol % SiO₂; from about 12 mol % to about 22 mol % Al₂O₃; up to about 6.5 mol % B₂O₃; up to about 1 mol % P₂O₅; from about 11 mol % to about 21 mol % Na₂O; up to about 0.95 mol % K₂O; up to about 4 mol % MgO; up to about 5 mol % ZnO; and up to about 2 mol % CaO. In the glass of the first aspect Na₂O+K₂O— Al₂O₃≤2.0 mol, B₂O₃—(Na₂O+K₂O—Al₂O₃)>1 mol %, 24 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag, and the glass is substantially free of TiOz.

A second aspect includes the glass of the first aspect wherein the glass is substantially free of at least one of P₂O₅ and Li₂O.

A third aspect includes the glass of the second aspect wherein the glass is substantially free of Li₂O.

A fourth aspect includes the glass of the first aspect wherein 56 mol %≤SiO₂+B₂O₃≤75 mol %.

A fifth aspect includes the glass of the first aspect wherein 2 mol %≤B₂O₃+P₂O₅7.5 mol %.

A sixth aspect includes the glass of the first aspect wherein the glass is ion exchanged and has a Vickers crack indentation threshold of at least about 9.5 kgf.

A seventh aspect includes the glass of the sixth aspect wherein the glass has a layer under compressive stress CS of greater than about 500 MPa, the layer extending from a surface of the glass to a depth of layer DOL, wherein CS·DOL=44000 MPa·μm.

An eighth aspect includes the glass of the sixth aspect wherein the glass has a compressive stress of greater than about 800 MPa and a depth of layer of at least about 40 μm, and has been ion exchanged for less than about four hours.

A ninth aspect includes the glass of the sixth aspect wherein the glass has a compressive stress of greater than about 800 MPa and a depth of layer of at least about 52 μm, and has been ion exchanged for less than about eight hours.

A tenth aspect includes the glass of the sixth aspect The glass of Claim 6, wherein the glass has a compressive stress of greater than about 800 MPa and a depth of layer of at least about 30 μm, and has been ion exchanged for less than about two hours.

An eleventh aspect includes the glass of the first aspect wherein the glass is substantially free of As₂O₃ and Sb₂O₅.

A twelfth aspect includes the glass of the first aspect wherein the glass further comprises at least one fining agent.

A thirteenth aspect includes the glass of the twelfth aspect wherein the at least one fining agent comprises at least one of SnO₂, CeO₂, As₂O₃, Sb₂O₅, Cl⁻, and F⁻.

A fourteenth aspect includes the glass of the thirteenth aspect wherein the at least one fining agent comprises at least one of up to about 0.5 mol % SnO₂, up to about 0.5 mol % As₂O₃, and up to about 0.5 mol % Sb₂O₃.

A fifteenth aspect includes the glass of the first aspect wherein the glass comprises: from about 55 mol % to about 62 mol % SiO₂; from about 16 mol % to about 20 mol % Al₂O₃; from about 2 mol % to about 6.5 mol % B₂O₃; up to about 1 mol % P₂O₅; from about 14 mol % to about 18 mol % Na₂O; from about 0.2 mol % to about 0.75 mol % K₂O; up to about 0.5 mol % MgO; up to about 0.5 mol % ZnO; and up to about 0.5 mol % CaO.

A sixteenth aspect includes the glass of the fifteenth aspect wherein Na₂O+K₂O—Al₂O₃≤0.5 mol %.

A seventeenth aspect includes the glass of the fifteenth aspect wherein B₂O₃—(Na₂O+K₂O—Al₂O₃)>4 mol %.

An eighteenth aspect includes the glass of the fifteenth aspect wherein the glass comprises from about 4 mol % to about 6.5 mol % B₂O₃.

A nineteenth aspect includes the glass of the fifteenth aspect wherein the glass has a liquidus viscosity of at least 100 kpoise.

A twentieth aspect includes the glass of the nineteenth aspect wherein the glass is down-drawable.

In a twenty-first aspect a glass comprises: from about 55 mol % to about 62 mol % SiO₂; from about 16 mol % to about 20 mol % Al₂O₃; from about 4 mol % to about 6.5 mol % B₂O₃; from about 14 mol % to about 18 mol % Na₂O; from about 0.2 mol % to about 0.75 mol % K₂O; up to about 0.5 mol % MgO; up to about 0.5 mol % ZnO; and up to about 0.5 mol % CaO. In the glass of the twenty-first aspect the glass is substantially free of P₂O₅, Na₂O+K₂O—Al₂O₃≤0.5 mol %, B₂O₃—(Na₂O+K₂O—Al₂O₃)>4 mol %, 28 mol %≤RAlO₄≤45 mol %, where R is at least one of Na, K, and Ag, and the glass is substantially free of TiO₂.

A twenty-second aspect includes the glass of the twenty-first aspect wherein the glass is substantially free of Li₂O.

A twenty-third aspect includes the glass of the twenty-first aspect wherein 56 mol %≤SiO₂+B₂O₃≤70 mol %.

A twenty-fourth aspect includes the glass of the twenty-first aspect wherein 0 mol %≤Σ[R′O]≤0.5 mol %, where R′ is at least one of Ca, Mg, and Zn.

A twenty-fifth aspect includes the glass of the twenty-first aspect wherein K₂O≤0.25(Na₂O+K₂O).

A twenty-sixth aspect includes the glass of the twenty-first aspect wherein the glass is substantially free of As₂O₃ and Sb₂O₃.

A twenty-seventh aspect includes the glass of the twenty-first aspect wherein the glass further comprises at least one fining agent, the fining agent comprising at least one of SnO₂, CeO₂, As₂O₃, and Sb₂O₅, Cl⁻, and F⁻.

A twenty-eighth aspect includes the glass of the twenty-seventh aspect wherein the at least one fining agent comprises at least one of up to about 0.5 mol % SnO₂, up to about 0.5 mol % As₂O₃, and up to about 0.5 mol % Sb₂O₃.

A twenty-ninth aspect includes the glass of the twenty-first aspect wherein the glass has a liquidus viscosity of at least 100 kpoise.

A thirtieth aspect includes the glass of the twenty-ninth aspect wherein the glass is down-drawable.

A thirty-first aspect includes the glass of the twenty-first aspect wherein the glass is ion exchanged and has a Vickers crack indentation threshold of at least about 9.5 kgf.

A thirty-second aspect includes the glass of the thirty-first aspect wherein the glass has a layer under compressive stress CS of greater than 500 MPa, the layer extending from a surface of the glass to a depth of layer DOL, wherein CS·DOL=44000 MPa·μm.

A thirty-third aspect includes the glass of the thirty-first aspect wherein the glass has a compressive stress of greater than about 800 MPa and a depth of layer of at least about 40 μm, and has been ion exchanged for less than about four hours.

A thirty-fourth aspect includes the glass of the thirty-first aspect wherein the glass has a compressive stress of greater than about 800 MPa and a depth of layer of at least about 52 μm, and has been ion exchanged for less than about eight hours.

A thirty-fifth aspect includes the glass of the thirty-first aspect wherein the glass has a compressive stress of greater than about 800 MPa and a depth of layer of at least about 30 μm, and has been ion exchanged for less than about two hours.

In a thirty-sixth aspect a method of ion exchanging a glass comprises ion exchanging an alkali aluminosilicate glass for up to about eight hours in an ion exchange bath at a temperature of about 410° C. or less, the ion exchange bath comprising a potassium salt and the alkali aluminosilicate glass comprising: from about 50 mol % to about 72 mol % SiO₂; from about 12 mol % to about 22 mol % Al₂O₃; up to about 6.5 mol % B₂O₃; up to about 1 mol % P₂O₅; from about 11 mol % to about 21 mol % Na₂O; up to about 0.95 mol % K₂O; up to about 4 mol % MgO; up to about 5 mol % ZnO; and up to about 1 mol % CaO. The ion exchanged alkali aluminosilicate glass has a compressive layer extending from a surface to a depth of layer DOL, the compressive layer having a compressive stress CS of at least 500 MPa, and the glass is substantially free of TiO₂.

A thirty-seventh aspect includes the glass of the thirty-sixth aspect wherein CS·DOL=44000 MPa·μm.

A thirty-eighth aspect includes the glass of the thirty-sixth aspect wherein the glass is ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 52 μm within eight hours ion exchange time.

A thirty-ninth aspect includes the glass of the thirty-sixth aspect wherein the glass is ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 40 μm within four hours ion exchange time.

A fortieth aspect includes the glass of the thirty-sixth aspect wherein the glass is ion exchanged to achieve a compressive stress of at least about 800 MPa and a depth of layer of at least about 30 μm within two hours ion exchange time.

While typical embodiments have been set forth for the purpose of illustration, the foregoing description should not be deemed to be a limitation on the scope of the disclosure or appended claims. Accordingly, various modifications, adaptations, and alternatives may occur to one skilled in the art without departing from the spirit and scope of the present disclosure or appended claims. 

1. A glass, the glass comprising: from 50 mol % to 72 mol % SiO₂; from 12 mol % to 22 mol % Al₂O₃; up to 6.5 mol % B₂O₃; up to 1 mol % P₂O₅; from 11 mol % to 21 mol % Na₂O; from 1.42 mol % to 3.21 mol % K₂O; up to 4 mol % MgO; up to 5 mol % ZnO; and up to 2 mol % CaO, wherein Na₂O+K₂O—Al₂O₃≤2.0 mol, and B₂O₃—(Na₂O+K₂O—Al₂O₃)>1 mol %.
 2. The glass of claim 1, wherein the glass comprises from 1.42 mol % to 2.19 mol % K₂O.
 3. The glass of claim 1, wherein the glass is substantially free of at least one of TiO₂, P₂O₅ and Li₂O.
 4. The glass of claim 1, wherein the glass is substantially free of Li₂O.
 5. The glass of claim 1, wherein 56 mol %≤SiO₂+B₂O₃≤75 mol %.
 6. The glass of claim 1, wherein the glass comprises from 1.49 mol % to 2.01 mol % K₂O.
 7. The glass of claim 1, wherein the glass is ion exchanged and has a Vickers crack indentation threshold of at least 9.5 kgf.
 8. The glass of claim 1, wherein the glass has a layer under compressive stress CS of greater than 500 MPa, the layer extending from a surface of the glass to a depth of layer DOL, wherein CS·DOL≥44000 MPa·μm.
 9. The glass of claim 1, wherein the glass is substantially free of As₂O₃ and Sb₂O₅.
 10. The glass of claim 1, wherein the glass has a liquidus viscosity of at least 100 kpoise.
 11. A glass comprising: from 55 mol % to 62 mol % SiO₂; from 16 mol % to 20 mol % Al₂O₃; from 4 mol % to 6.5 mol % B₂O₃; from 14 mol % to 18 mol % Na₂O; from 1.42 mol % to 3.21 mol % K₂O; up to 0.5 mol % MgO; up to 0.5 mol % ZnO; and up to 0.5 mol % CaO, wherein the glass is substantially free of P₂O₅, Na₂O+K₂O—Al₂O₃≤0.5 mol %, and B₂O₃—(Na₂O+K₂O—Al₂O₃)>4 mol %.
 12. The glass of claim 11, wherein the glass comprises from 1.42 mol % to 2.19 mol % K₂O.
 13. The glass of claim 11, wherein the glass comprises from 1.49 mol % to 2.01 mol % K₂O.
 14. The glass of claim 11, wherein the glass is substantially free of at least one of Li₂O and TiO₂.
 15. The glass of claim 11, wherein 56 mol %≤SiO₂+B₂O₃≤70 mol %.
 16. The glass of claim 11, wherein 0 mol %≤Σ[R′O]≤0.5 mol %, where R′ is at least one of Ca, Mg, and Zn.
 17. The glass of claim 11, wherein the glass is substantially free of As₂O₃ and Sb₂O₃.
 18. The glass of claim 11, wherein the glass has a liquidus viscosity of at least 100 kpoise.
 19. The glass of claim 11, wherein the glass is ion exchanged and has a Vickers crack indentation threshold of at least 9.5 kgf.
 20. The glass of claim 11, wherein the glass has a layer under compressive stress CS of greater than 500 MPa, the layer extending from a surface of the glass to a depth of layer DOL, wherein CS·DOL≥44000 MPa·μm. 